Story 276: Twice Upon A Time

In which the Doctor, refusing to regenerate after being mortally wounded by Cybermen, finds himself at the South Pole. It is December 1986, and out of the icy fog emerges one of his earlier selves - his first incarnation. He has just come from his first encounter with the Cybermen, and is battling against his own impending regeneration.

Whilst the two argue over what they are doing here, time seems to stand still as they see snowflakes suspended in the air. A British Army Captain of the First World War then wanders towards them, unaware of how he came to be here. The last he remembers was being trapped with a German soldier in a foxhole - about to kill each other - when time had stood still for him as well. He had then been approached by a bizarre female figure who appeared to be composed of glass.

The Doctor takes them both into his TARDIS. The First Doctor is not impressed with it, or with the fact that this is his future incarnation.

A gigantic spacecraft appears overhead and it lowers a huge hydraulic claw which seizes the TARDIS and pulls it aboard.

They hear a voice asking them to come outside to the Chamber of the Dead.

The Doctors are offered a gift in return for handing over the Captain - Bill Potts. The Doctor knows that she cannot be real, but she insists that it is the real her.

The Doctors discover time-travel technology of advanced design.

The glass woman appears and explains that the Captain must be returned to the time and place of his death. The First Doctor is given a glimpse of his future selves, learning that he will be known as the "War Doctor", which appals him.

The Doctor manages to open the hatch through which they were brought on board and they use the claw cable to descend to the ice beneath. They take to the First Doctor's TARDIS and dematerialise.

The Doctors wish to know who this glass woman is and what her motives might be. She looked like she was based on a humanoid original so the Doctor decides they must seek out the greatest database in the universe - and he knows where to find it.

The ship arrives on the planet of Villengard, amongst the ruins of its famous weapons factories. A ruined tower is under attack from Daleks, many of which have lost their casings. The Doctor will go there himself as he knows the occupant. In the TARDIS, it is revealed that Bill is really the glass female in disguise.

At the top of the tower the Doctor finds the Dalek which he had previously nicknamed "Rusty".

It has carried on its campaign against its own kind and has amassed a huge databank of knowledge in the meantime. It is able to identify the woman they seek as Professor Helen Clay. She helped found the Testimony Foundation which collects the memories of the dead and allows them to speak again through glass avatars. In this way, everyone has a chance to live on after death.

There is nothing evil behind what she seeks with the Captain.

Time is made to stand still once again, and the two Doctors travel with the Captain to the WWI battlefield. Here the Doctor learns that the man is a member of the Lethbridge-Stewart family - the Brigadier's grandfather.

He has returned to his foxhole, resigned to die, but the Doctor has nudged time on a few minutes. It is Christmas 1914, and the fighting stops for the festive armistice. The Captain is saved.

The First Doctor departs, ready now to face his regeneration after seeing a glimpse of his future.

Before "Bill" departs, she gives the Doctor a final gift. He sees Nardole - and Clara, memories of whom are returned to him.

He, too, is now ready to face his regeneration. With the TARDIS in flight he regenerates into a female form. The ship goes out of control and the new Doctor falls out of the open doors...

Twice Upon A Time was written by Steven Moffat - his final contribution to the series at time of writing - and was first broadcast on Monday 25th December 2017.

Moffat had thought that his final story, and that of Peter Capaldi's Twelfth Doctor, was to be The Doctor Falls. This was the second half of an epic series finale featuring the return of the Mondasian Cybermen and of the Harold Saxon incarnation of the Master, with the Doctor repeatedly blasted by Cybermen, Bill Potts transformation and departure, and the two incarnations of the Master killing one another. Ordinarily, this would have been an ending, but it would prove to be just a step towards the final end for actor and writer, which would be prolonged until Christmas.

Moffat had expected his successor, Chris Chibnall, to launch his iteration of the series, with the new female Doctor, at Christmas 2017. Christmas night was the prime time of prime time, a slot which the series had won back in 2005 and held onto ever since - even when there hadn't even been a normal series that year.

However, Chibnall simply wasn't ready to produce a Christmas Special, and was contemplating doing away with them altogether anyway. Ratings for Christmas night were falling across the board, not just for Doctor Who. The soaps and the sitcom Mrs Brown's Boys were also seeing lower viewing figures, despite still maintaining good percentage scores.

In order to keep the slot, Moffat agreed to write one more story, and since the Doctor was already dying, he would prolong the regeneration for one more adventure and build an episode around this.

Moffat had earlier been asked about returning characters during a Comic-Con panel, when he stated that a meeting between the first and last Doctors - both famed for their grumpiness - would be a great idea.

Peter Capaldi then said that he knew who they could get to play him... This was David Bradley, who in 2013 had portrayed William Hartnell / the First Doctor in An Adventure in Space and Time.

The First Doctor had already been played by another actor, when Richard Hurndall had taken on the role for The Five Doctors. With the theme of regeneration already in place, the obvious storyline of two Doctors each facing their impending regenerations, but refusing to accept them, presented itself. This in turn led to the setting of the South Pole (scene of the Doctor's first regeneration at the conclusion of The Tenth Planet, which coincidentally featured the Cybermen). The meeting of the two Doctors would make for a special end of series cliff-hanger, and material was prepared to top and tail the Series 10 finale. The moment chosen was the sequence at the end of the fourth episode when the Doctor wanders off alone to the TARDIS before companions Ben and Polly can catch up with him, once he's already in the ship. Having just brought back the Mondasian Cybermen, the costumes existed to allow a recreation of scenes from the 1966 story, similar to those staged for the 50th Anniversary drama.

Several scenes were filmed, but few made it to the final episode. These were the introductory sequence where Hartnell's features blend into Bradley's, following the "Have you no emotions?" speech; and the regeneration itself, which existed as some 8mm off-air material and a clip preserved through inclusion in Blue Peter's coverage of Doctor Who's 10th Anniversary in 1973.

As a swansong for writer and actor, the episode was to include references to earlier stories. 

The episode opens with the caption "Previously on Doctor Who... 709 episodes ago", and we see footage from The Tenth Planet.

Other than those relating to the First Doctor, the biggest nod to the more recent past was the inclusion of "Rusty" - the Good Dalek - which had featured right at the start of Capaldi's tenure in the TARDIS, Inside the Dalek being only his second story. The location of Villengard went back to Moffat's very first story for the series in 2005. 

In The Doctor Dances the Doctor and Captain Jack discuss its weapon factories and their destruction.

Thanks to cuts we hardly see Ben (Jared Garfield) or Polly (Lily Travers).

On a personal note, two of Moffat's friends and fellow writers - the most prolific - just happened to also act. Mark Gatiss featured as the Captain, who we would subsequently learn is an ancestor of Brigadier Lethbridge-Stewart; and Toby Whithouse played his German army opponent.

Captain Lethbridge-Stewart lives in Cromer, the Norfolk town which his grandson will think UNIT HQ has been transported to in The Three Doctors.

The idea of the glass avatar (Testimony / Helen Clay being played by Nikki Amuka-Bird, who had featured in the Torchwood episode Sleeper) allowed for a reappearance of Pearl Mackie as Bill, and we also saw an image of Clara, with the Doctor regaining his memories of her. To round off the season, Nardole also appears to say goodbye to the Doctor, bringing all of their stories to a conclusion. It should be remembered that the Doctor was unconscious when taken into the TARDIS at the end of The Doctor Falls, so won't have been aware of the fates of Bill and Nardole. 

The Testimony Foundation is said to have been formed on New Earth. The Chamber of the Dead is able to show the First Doctor his future selves, allowing for clips of other Doctors.

One criticism of the story was the realisation of the First Doctor in terms of his old-fashioned attitudes. Bradley is given words which the First Doctor would never have uttered - but which the actor who played him might have done (e.g. the sexist remarks). It does seem as though Moffat has confused actor with character.

The series had been struggling to include festive components in its Christmas Specials, but the 1914 WWI armistice at Ypres, when troops from both sides ceased hostilities to party together and play football, hadn't been used so far. 

Overall, a nostalgic end to the Moffat / Capaldi eras. The actual story is quite weak, but that doesn't really matter. It's a farewell story in more ways than one, the end of an era. There are many who dislike (indeed, hated) what happened next, and this episode is now seen by some as the last of its particular line.

Things you might like to know:

• Peter Capaldi was invited to stay on when he learned that Moffat was leaving. It was only coincidence that the two left together. Capaldi decided that his three series were enough, and wanted to move on to other projects.
• This episode was so unplanned that both Pearl Mackie and Matt Lucas believed they had finished on the series and were pleasantly surprised to be invited back. Mackie was on holiday in the US when asked to return, and Lucas in Rome writing his autobiography.
• Rachel Talalay had already directed the Series 10 finale and was keen to get home, but Moffat and Capaldi together talked her into remaining in the UK to direct this story.
• Sadly, this was the final Doctor Who story to be designed by Michael Pickwoad. He passed away in August 2018.
• We see a ring drop from the new Doctor's hand just after she has regenerated - a nod to the same thing happening in Power of the Daleks.
• Unlike when Ten became Eleven, it isn't the regeneration which wrecks the TARDIS. It's only afterwards when the Doctor presses a button that the console explodes and it goes out of control - Chibnall intending, like Moffat before him, to have his own new console room.
• In the first draft there's a funny reference to Episode 3 of The Tenth Planet when the First Doctor seems to brag about his actions at Snowcap Base, to which the current Doctor remarks that all he did was have a big nap - Hartnell having fallen ill and the Doctor been written out of that episode, stuck unconscious in bed.
• As the Doctor sends a message to his future self, he quotes Terrance Dicks' famous words about the Doctor never being cruel or cowardly. He also advises never eating pears, which was on Ten's recorded to-do list in Human Nature.
• The Testimony Foundation was formed in the year 5 Billion and 12, which is before the events seen in either of the televised stories set on New Earth - so before the population was decimated by the mood virus.
• The difference in facial features of the First Doctor is put down to the early effects of the regeneration process. Their timelines being "out of synch" is the excuse why the Second Doctor will not remember any of these events.
• Testimony gives some of the titles which have been given to the Doctor, most of which we know of ("Destroyer of Worlds" was given him by Davros, for instance). However, two titles refer to stories we have never seen - "The Last Tree of Garsenon" and "The Butcher of Skull Moon".
• BBC VFX pioneer Bernard Wilkie's name appears on a label on the TARDIS console.
• Some of the set elements, like the brass columns, seen in the First Doctor's TARDIS are the original ones from 1963.
• Jon Pertwee's purple jacket from Planet of the Spiders is seen in the TARDIS. Capaldi was photographed by Mark Gatiss (who now owns it) wearing it in his trailer:

Story 275: World Enough And Time / The Doctor Falls

In which the Doctor decides to let Missy lead an expedition in the TARDIS. He will remain in the ship whilst she takes charge, accompanied by Bill and Nardole. This is all part of the Doctor's attempts to rehabilitate his old frenemy.

The ship is responding to a distress signal, and materialises in a control room. Missy must investigate and work out where they are, whilst the Doctor listens in. They have landed on the command deck of a vast cylindrical spacecraft - 400 miles long - which appears to be stationery in space, sitting on the edge of a Black Hole. Its engines are actually straining to move it slowly away and prevent it from being sucked into the phenomenon. 

A blue-skinned humanoid appears. Jorj is a janitor, and he has been on his own for two days, after his colleagues descended in a lift to the lower levels. He is armed, and appears frightened. He is concerned that one of the trio is human, which has attracted someone who is ascending in one of the lifts. Realising the danger he poses in this state, the Doctor emerges from the TARDIS. Jorj panics and shoots Bill, blasting a hole through her chest. The lift doors open and masked figures emerge, taking Bill away with them.

Nardole checks the monitors and discovers that there are thousands of life forms on the lower levels of this craft - the end furthest away from where they have landed.

There are hundreds of levels, each containing its own biosphere.

Bill wakes to find herself in a hospital, with a bulky artificial heart and lung unit attached to her chest. Exploring, she finds wards full of heavily bandaged figures. She is horrified to discover that they are silently crying out in pain. They long for death.

Looking out of a window she sees a nocturnal cityscape - a heavily industrialised area. A man named Razor introduces himself to her. He explains that she was brought to the lower levels of the spaceship some time ago. The other patients are in the process of being cured. He agrees to take her in.

In the control room, only a few seconds have passed since Bill was taken away. The Doctor realises that the ship is so large that time is moving at different speeds at either end of the craft, due to the effects of the gravitational pull of the Black Hole. Whilst minutes pass here, months or even years may pass at the other end.

The life signs Nardole detected are descendants of Jorj's original colleagues. The Doctor calls a lift, intent on searching for Bill. He is knocks Jorj out when he tries to stop the lift being called.

Bill is able to see the control room on a scanner Razor has set up, but the Doctor, Nardole and Missy look like they are frozen, with time passing so slowly in relation to where she is.

He explains that all of the people on this level are undergoing medical procedures in order to embark on a mass exodus to higher levels.

Ten years pass for Bill. Seeing that the Doctor has gone to the lift, Razor pretends to take her to the lift door on this floor to meet him. However, he delivers her instead to an operating theatre where she is told that she is to undergo a full upgrade.

The others arrive. Whilst the Doctor and Nardole go in search of Bill, Missy begins checking the computers. She discovers that this craft was a colony ship from the planet Mondas...

Razor appears and asks her if she recalls having been here before. He removes a mask to reveal that he is the disguised Master - her previous incarnation. 

The Doctor is confronted by a Mondasian Cyberman in the operating theatre, escorted by Missy and the Master. He is horrified to discover that the Cyberman is Bill...

The Doctor is taken up to the roof of the hospital where the Master explains that the Cybermen have evolved on this ship, and their 'Operation Exodus' is the planned invasion of the higher levels. They will take the entire ship, converting all the humanoids they encounter as they move towards the command deck. On Level 507 there is an agricultural zone, where the humanoid inhabitants struggle to prevent Cyberman incursions.

Missy knocks out the Master as Cybermen attack. They have always ignored non-human lifeforms, but the Doctor had altered their programming to make Time Lords just as vulnerable to conversion as human beings. The Doctor is blasted by a Cyberman, but Nardole arrives in a shuttlecraft. The three Time Lords and the Bill-Cyberman enter it and it takes off - punching its way up through a number of floors before crashing on Level 507.

Two weeks pass. Bill has been unconscious and wakes to find herself in barn where she meets a woman named Hazran. She looks after a group of children, and defends this level. She explains that Bill is kept outside their farmhouse as she frightens the children, and Bill sees her reflection in a mirror - that of a Cyberman. She had blocked her fate from her mind. The Doctor notes that she has managed to retain her human emotions.

As Nardole helps Hazran prepare defences against the full invasion, the Master leads Missy and the Doctor into the woods near the farm. The latter is concealing that the injury he received from the Cyberman on the roof was actually terminal, and he is holding back his regeneration. The Master shows them both a lift entrance, and suggests they use it to find the Doctor's TARDIS and escape. His own ship is disabled on the hospital floor, its dematerialisation circuit burnt out. Missy carries a spare - due to a vague memory of these events.

The Doctor thinks they will never reach the TARDIS alive, and he wants to stay and help defend Hazran and the children. He asks his fellow Time Lords to join him. The Master and Missy refuse, and set off for the lift.

A number of booby-traps destroy some of the Cybermen, many of whom have evolved into more advanced versions. The Doctor orders Nardole to guide Hazran and the children to an upper level, as he plans to destroy this one with all the Cybermen concentrated in one location - even though he is likely to perish himself in doing so.

At the lift, the Master and Missy betray each other. She has taken on board much of what the Doctor had done to rehabilitate her, whilst he hates what the Doctor has done to his future self. They kill each other. The dying Master descends to the hospital level to find his TARDIS, where he will regenerate into her, whilst she is left for dead in the woods - the Master having ensured that she can no longer regenerate.

Nardole leads Hazran and the children to Level 502, whilst the Doctor and Bill battle the Cyberman army. He is shot several times, but manages to blow up the Level. Bill finds his body and takes it to the TARDIS. 

The water entity Heather appears, never having lost contact with Bill. The pair will travel the universe together, with Bill transformed into an ethereal being like her.

The Doctor wakes up in the TARDIS, and emerges to find himself in a bleak snowy wasteland. He refuses to regenerate. A figure approaches through the icy fog, and he is shocked to see that it is his own first incarnation...

World Enough And Time / The Doctor Falls were written by Steven Moffat, and first broadcast on 24th June and 1st July, 2017.

They brought the tenth season of the revived series to a close, and marked the final appearances (to date at least) of Michelle Gomez as Missy, and John Simm as the Master. The story also introduced David Bradley as the First Doctor, after the actor had previously portrayed William Hartnell in the 50th Anniversary drama An Adventure in Space and Time.

The episodes were also supposed to mark the departure of Peter Capaldi as the Twelfth Doctor, regenerating at the conclusion due to multiple blasts by Cyberman attackers. 

Steven Moffat had assumed that his successor as show-runner was going to write the 2017 Christmas Special, presumably introducing the Thirteenth Doctor. However, Chris Chibnall informed him that he was going to pass on writing a Christmas episode and would not be providing his first story until the Spring of 2018. Not wanting to see the series lose the prestigious Christmas night prime-time slot, in which had fared well in the ratings, Moffat hurriedly altered the ending of The Doctor Falls so that it would segue into a new final story for Capaldi, to be screened on 25th December.

Capaldi had earlier stated that the original Cybermen were one of his favourite monsters from the classic era of the series, and he'd love to see them make a return. These were the costumes designed by Sandra Reid for The Tenth Planet in 1966, characterised by blank cloth faces. He had suggested to Moffat that they could do the costume much better nowadays with current materials. 

By way of a thank-you to his departing star, and because he himself was leaving, Moffat elected to write a story which included the Mondasian Cybermen. This would also act as a Cyberman origins story - an idea first mooted by their co-creator Gerry Davis back in the mid 1980's. This time it was Capaldi who suggested it - possibly inspired by the Big Finish audio Spare Parts. 

Moffat re-read Davis' Doctor Who and the Cybermen which demonstrated how the Cybermen simply wanted to survive. The two newer versions of Cyberman could be included as the creatures would be seen to evolve.

Cybermen had featured in a number of series finales since Moffat took over - or the penultimate episode of the season: The Big Bang, Closing Time, Nightmare in Silver, Dark Water / Death in Heaven, and Hell Bent.

The story would be seeing the conclusion to the Missy story arc - and the departure of Gomez. To make this series finale even bigger, Moffat decided to deliver a "Two Masters" tale, bringing back John Simm as the previous incarnation. He had last been seen in The End of Time Part II,  leaving the show with David Tennant and Russell T Davies. At the time he had claimed that he would not be returning - as Gomez was to claim on the occasion of her departure.

As a nod to the Delgado and Ainley incarnations, Simm sported a goatee beard this time. The use of disguises was another of their traits.

The Master states that before he left Gallifrey, the Time Lords cured him of the persistent drumming in his head - hence why it hasn't affected Missy of the Sacha Dhawan incarnation. They no longer have the X-ray skeleton effect which we saw in The End of Time.

Presumably the Master had stolen his new TARDIS from Gallifrey, as he had not been seen to possess one since The Mark of the Rani (though not seen on screen, he must have used it to get to 18th Century Northumbria). Missy's failure to recall any of the events here, involving as they do her earlier self (apart from her unconsciously carrying of a spare dematerialisation circuit) can only be explained by the trauma of their mutual destruction of each other, though it isn't terribly clear.

It was originally intended that Simm's return would be a closely guarded secret, but then the BBC released the news as they thought he would be spotted on location. As it was, no-one did notice, so the return was spoiled by the production team themselves.

Other than the rogue Time Lords already mentioned, there are two additional guest artists of note. Playing Hazran is Samantha Spiro, who had recently played Carry On... star Barbara Windsor in biographical drama Babs, having previously played her in an earlier biopic titled Cor, Blimey! about the relationship between Windsor and Sid James. And Stephanie Hyam returns from The Pilot to play Heather.

Jorj is played by Oliver Lansley, and the surgeon and nurse who upgrade Bill are Paul Brightwell and Alison Lintott respectively.

Overall, an excellent pair of episodes that would have made for a fitting swansong for Peter Capaldi's Doctor. Lots to please long term fans with references to the classic series and even spin-off material. The Mondasian Cybermen may be slightly over-designed, in comparison with the originals, but Moffat gives them a great origins tale. Recently voted the top Capaldi story in the DWM 60th Anniversary polling.

Things you might like to know:

• "World enough and time" is a line from the 1681 poem To His Coy Mistress, by Andrew Marvell. In it, the poet promotes living life to the fullest as death may be just round the corner. It was published posthumously.
• One of the reasons John Simm agreed to return to the programme was because he was disappointed not to have been involved in the 50th Anniversary.
• It was assistant director Michael Williams who coined the phrase "Mondasian Cybermen". 
• Moffat addresses Cyberman continuity by claiming that whilst they evolved on Mondas, they came into being on many other worlds as well, quite independently. Wherever there are humanoids struggling in adverse conditions, there is the potential for them to resort to cybernetic implants to survive.
• Planet 14, mentioned in The Invasion as somewhere the Cybermen once encountered the Doctor, has long been puzzled over by fans. Is it the Moon? Is it Telos? Is it the scene of some unscreened adventure? According to this story, it's simply another planet where Cybermen evolved.
• Marinus is also mentioned, tying in with a DWM comic strip - "The World Shapers" - in which Voord evolved into Cybermen.
• The Doctor also mentions places where he has defeated the Cybermen in the past, which include Telos (Tomb of the Cybermen and Attack of the Cybermen), the Moon (The Moonbase) and Voga (Revenge of the Cybermen).
• According to this story, it is the handlebar attachments on the Cybermen which act as the emotional inhibitors. In The Tenth Planet they simply held the head lamp in place.
• Amongst the silly names Missy uses for Bill and Nardole, she calls them "Exposition" and "Comic Relief", which just happen to be two story functions of the companion character.
• The scenes in the snowy wasteland with David Bradley were shot during the making of the Christmas Special, and only edited into these episodes just before broadcast.
• Earlier regenerations are referenced. The Doctor talks of Sontarans perverting the course of history as he wakes up in the TARDIS (as with the Fourth in Robot); says "No!" - the final word of the Second Doctor; and "I don't want to..." - as in Ten's "I don't want to go".

Story 274: The Eaters of Light

In which the Doctor takes Bill and Nardole to North-East Scotland in the Second Century AD. Bill has always been fascinated by the story of the Ninth Legion, which is supposed to have vanished without trace in this region whilst fighting the native Pictish peoples. The Doctor wishes to prove to her that there was no mystery to this event - they were simply killed in battle.

Bill wanders off by herself and comes across a young woman named Kar who is conducting a ceremony honouring the dead of her tribe. She attacks Bill who is forced to flee through the woods. She falls down a hole, finding herself in a maze of natural tunnels. She comes upon a young Roman soldier named Simon. He warns of a strange creature which has attacked his comrades.

The Doctor and Nardole, meanwhile, have come across a cairn. The Doctor explains that these were often used as markers for portals to other worlds.

They then find a battlefield, strewn with dead bodies. The corpses do not show the usual signs of battle, however. They have been totally drained of their lifeforce. The skin shows unusual pigmentation.

They then see a group of Pict warriors approach. They are captured and taken to their village, where they find Kar in command.

Simon helps Bill out of the tunnel, and tells her to look for a stone etched with a fish symbol - which marks the entrance to a cave where his comrades have taken refuge from the Picts. The hole she fell through was a trap dug by the locals. As they are about to move off through the woods, a large quadruped covered in glowing tentacles attacks. Simon is seized by a tentacle, and has his lifeforce sucked from his body. Bill manages to find the marker stone and enters the cave, where she encounters more young Roman soldiers, led by Lucius.

At the village, Kar claims to have destroyed the invading Roman army. She is known as the "Keeper of the Gate" by her younger brother Ban and the rest of the villagers. Creating a diversion by throwing some popcorn onto the fire, the Doctor and Nardole escape. They go to the cairn and the Doctor goes inside alone. A wall slides open to reveal a bizarre blue void beyond. He then sees some creatures floating around within it. 

On leaving the cairn a few minutes later, the Doctor is shocked to find that two whole days have passed.

Nardole has "gone native" and befriended the Picts, but Bill is still missing. She has been making friends with the Roman youths. Lucius has told her of how he and the others had been terrified and had fled the field of battle.

The Doctor learns from Kar that the creatures within the cairn are known as the "Eaters of Light" as they seem to absorb the sunlight from around themselves. Every generation sees a Pictish warrior enter the void to hold the creatures at bay. The Doctor has already deduced that time moves at a much slower rate beyond the wall. Kar tells him that she released one of the creatures to kill the Romans, but now that it is free it has been killing her own people as well. 

The creature attacks Bill and her new friends and they are forced to flee through the cave system to a point beneath the village. They find a ladder leading up and emerge within the Picts' great hall. The Doctor steps in to prevent the two sides fighting each other - explaining that they have a common enemy now. 

They must join forces to defeat the creature. At dawn it will absorb sunlight and grow strong. It must be forced back into the void.

The Doctor works out that a certain type of crystal will produce a wavelength of light which should prove unpalatable to the creature. They lure it into the cairn and attack it with staffs mounted with these crystals. They will push it back into the void once the wall opens. The Doctor will take the place of the Pictish warrior as for him the time differential will not matter so much. However, Kar has decided that she must be the one to do this, to atone for her actions in releasing it in the first place. Some of her warriors and musicians will join her. Lucius announces that he and his men will also accompany her, to atone for their cowardice in fleeing the battlefield. The Doctor is knocked out to prevent him from interfering with their plan.

After they have all passed through into the void, the cairn collapses. Bill and Nardole manage to get the Doctor outside as it does so. Ban claims that his sister and her friends will be immortalised in their stories - as will the Doctor.

In the present day, some visitors to the cairn report hearing the faint sound of Pictish music coming from beneath the ground, and the crows appear to be calling the Doctor's name. An object like a police box is carved on a nearby standing stone.

Back at the TARDIS, the Doctor and his companions find Missy waiting for them. The Doctor urges her to listen to the music of the Picts which the ship can pick up. Impressed by the courage and self-sacrifice it represents, she cannot help shed a tear...

The Eaters of Light was written by Rona Munro, and was first broadcast on Saturday 17th June 2017.

Munro was the writer of Survival - the final broadcast story of Doctor Who's original run in 1989.

This makes her the first person to have written for both the classic series and the revived one. (To date, she's the only writer who can claim this, and this may well remain the case as so many of the classic writers are no longer with us).

A parallel can be drawn between Munro's two stories in that both revolve around young people in a fight for survival.

Munro hails from Aberdeen, the biggest city in NE Scotland, and has an interest in local history and mythology.

Interested in writing for the series when it returned, the writer met Steven Moffat and Russell T Davies at the Edinburgh Festival in August 2006. Recalling this after he had taken over as show-runner, Moffat had recalled how Survival had shaken up the classic series - laying some of the foundations for the revival. 

Having studied History, Munro wanted to submit a story with a historical backdrop. She remembered how interested she had been with Rosemary Sutcliff's novel The Eagle of the Ninth (1954) which fictionalised a genuine historical mystery. The Legio IX Hispana had disappeared entirely from records after 117 AD, its last sighting supposedly on campaign against the Picts, who ruled northern and eastern Scotland.

A famous battle had been fought between Roman and Pict at Mons Graupius around 83 AD, and archaeologists had struggled to pinpoint the exact location for this. 

As a local, Munro was also interested in the Pictish culture, which left no written records but many mysterious rock carvings. One of these, of a strange quadruped creature, inspired the Eaters.

The guest cast is a youthful one. Apart from the regulars, all of the adult performers are background artists.

Leading the cast, playing Kar, is Rebecca Benson. She has appeared in crime dramas Vera and Shetland, and featured alongside Michael Fassbender in a 2015 version of Macbeth. Daniel Kerr plays her brother Ban. He has appeared in Outlander.

The Roman Legionaries are led by Brian Vernal as Lucius. He features prominently in Star Wars: The Force Awakens as Bala-Tik, and also appeared in Dunkirk and the 2017 remake of Papillion. He was a regular in the historical drama The Last Kingdom, and more recently has appeared in Gangs of London.

Rohan Nedd plays Simon. Other Roman soldiers are Ben Hunter, Sam Adewunmi, Billy Matthews and Aaron Phagura.

After her brief appearance at the conclusion of Empress of Mars, piloting the TARDIS, this week we see that Michelle Gomez's Missy is still in the ship. She has been trusted to remain there whilst the Doctor and his companions have been off exploring the Scottish countryside. 

This is all part of her rehabilitation, which will culminate next time when she is permitted to lead an expedition.

Munro opted to illustrate the differences in attitudes to sexuality between antiquity (the Romans) and the present (Bill). Two of the young Roman soldiers are boyfriends, and their comrades simply treat this as a matter of fact. The modern Bill knows that things are actually far harder in her time. (Whilst fluid sexuality was accepted in ancient times for the most part, effeminacy in men was frowned upon). 

Overall, an enjoyable enough story, often overlooked as it follows a big Ice Warrior story and comes before the Cyberman / Master finale. As a Scot interested in history - especially the Roman period - I am biased in favour of it. The lack of adult guests might also put some people off.

It didn't do very well in the recent DWM Twelfth Doctor poll for the 60th Anniversary, but it is certainly well worth a watch.

Things you might like to know:

• The Picts don't actually feature in Roman writings until the Third Century AD, but Munro used them as shorthand for the audience. 
• In Celtic mythology ancient structures like cairns and barrows are often claimed to be of Fairy construction - "Fairy Forts". Many tales tell of someone walking past hearing music coming from within them. When they enter they find themselves attending a feast of some sort. When they finally leave after what they believe to be a few hours they find that a whole year (or longer) has actually passed - which gave Munro the idea for the temporal differential in the void.
• Kar was originally called Ke in draft scripts. "Kar" fitted in better with the crow sounds.
• The association between crows and Celtic mythology had previously been seen in The Stones of Blood.
• The Doctor mentions having visited Aberdeen in the past. He had dropped Sarah Jane Smith off in the city, mistaking it for South Croydon, in The Hand of Fear, and then mentioned the Granite City to Leela in Underworld.
• Wanting to surprise her parents with an appearance in Doctor Who, Rebecca Benson claimed to be going to Cardiff to shoot pick-up shots for the series The White Princess which she had featured in. Even during a tour round the Doctor Who Experience with them she kept quiet about her new role.
• Nardole tells Ban and his friends the story of the Mary Celeste. It involves alien intervention - but not the "true" incident with the Daleks.
• Moffat joked with Munro that the last time she wrote for the series it was cancelled soon after - hoping that history would not repeat itself.
• You can fit the entire classic series into the gap between Munro's two stories - 27 years, 6 months and 11 days.

Story 273: Empress of Mars

In which the Doctor, Bill and Nardole learn that NASA have discovered a message on Mars. Written across the surface, using boulders, is "GOD SAVE THE QUEEN". They take to the TARDIS and travel to the planet as it was in 1881 when the message first appeared, materialising in an underground tunnel where they find a breathable atmosphere. Bill plunges down a hole in the ground and the Doctor sends Nardole back to the ship to fetch some rope. Once inside, the TARDIS suddenly dematerialises on its own. He is unable to control it, so the Doctor and Bill are trapped on Mars until he can sort it out.

The Doctor is confronted by an Ice Warrior, whilst Bill encounters a British soldier named Catchlove in the gallery below.

The Doctor meets another soldier - an officer named Godsacre - who reveals that the Ice Warrior is a friend, who his men have named "Friday", after the Robinson Crusoe character. The Warrior has a distinctive scar down his helmet.

The TARDIS has arrived back at St Luke's University. Unable to operate it himself, Nardole reluctantly approaches the Vault to seek help from Missy.

The Doctor and Bill are reunited in a cavern in which the British soldiers have established their camp. Friday acts as a servant to them. At dinner, Colonel Godsacre and Captain Catchlove reveal that they had been on a mission in South Africa where they had come across a crashed spaceship and its injured pilot - Friday. The Ice Warrior had convinced them that it could give them access to great mineral wealth if they helped it repair its ship. They could come with him to Mars, claiming the planet for their Empress and take what precious metals and gems they wanted.

They were now methodically mining the tunnels beneath the surface in search of the wealth which Friday had promised. To aid them, they are using some of his technology in the form of a huge sonic cannon which they have nicknamed the "Gargantua".

Despite being the senior officer, the Doctor notes that Catchlove does not treat Godsacre with the customary respect due a superior, but Godsacre does not react. 

The gun's operators - Sergeant Major Peach and privates Jackdaw and Vincey - succeed in breaching a rock wall and find a huge chamber beyond. It appears to be a burial vault. Large crystal sarcophagi line the walls and in the centre is a funeral bier on which lies a golden statue of a female Ice Queen.

The bier is covered in precious jewels. Jackdaw drugs Peach's drink, knocking him out. He has decided to raid the jewels for himself. As he removes the stones, a change comes over the statue. The gold decoration falls away to reveal an actual Ice Warrior body - and it is not dead. Queen Iraxxa is in suspended animation. She awakes and kills Jackdaw. Friday then appears. He has planned her resurrection - and the rest of his people - all along, exploiting the greed of the soldiers to get him back to Mars. In each of the sarcophagi is a dormant Ice Warrior, and Iraxxa activates the reanimation machinery.

On discovering what has happened, the Doctor attempts to make peace - telling the Queen that she should accept the help of the humans. However, one of the soldiers panics and opens fire, so Iraxxa declares war.

Catchlove wants to use the Gargantua against the Warriors, but Godsacre agrees with the Doctor on making peace. The Captain reveals to the rest of the men that their Colonel is really a coward. He always wears a neckerchief, which hides the fact that he survived a botched hanging for desertion. He is locked up in a cell with the Doctor and Bill as Catchlove takes over.

The Ice Warriors attack the soldiers by burrowing up through the ground behind their defences. Peach is killed, and Catchlove flees by throwing Vincey into their path to aid his escape. The young man perishes. Despite his loyalty to his Queen, Friday has come to respect the Doctor and it frees him and the others from the cell. Bill attempts to negotiate with Iraxxa giving the Doctor time to come up with a plan. He takes control of the Gargantua and threatens to destroy the ice Warrior hive unless a peaceful solution is found. Catchlove dons a spacesuit and hold the Queen hostage, intent on stealing the spaceship which they have been building on the surface to get back home. Godsacre shoots him dead, then offers himself to Iraxxa. He will submit to execution if his men are allowed to go free. The Queen admires this act, and finally agrees that the humans are worthy of making peace with.

Mars is dying, so the Ice Warriors must relocate. The Doctor sends out a message for help, which is answered by an inhabitant of Alpha Centauri, who welcomes the Martians to the Galactic Federation. Godsacre and his surviving men will leave with them. Before they go, they leave the message on the surface that will later be found by NASA.

The TARDIS suddenly reappears, and the Doctor is shocked to find Missy at the controls...

Empress of Mars was written by Mark Gatiss, and was first broadcast on Saturday 10th June 2017.

Gatiss had previously reintroduced the Ice Warriors in Series 7 with Cold War, and had always intended to revisit the aliens at some point. He had successfully added a lot to their mythology via references in some of his earlier stories, though his decision to show that they wore armour and were really badly CGI'd Gollum-like creatures underneath did not go down quite so well. 

What Gatiss had not planned was that his next Ice Warrior story would feature in Series 10. The original plan for this year had been to produce a sequel to Series 9's Sleep No More. This would have been set on contemporary Earth, with businessmen devising the same sort of technology which Rassmussen would create in the far future. Unfortunately Sleep No More had been panned by fans and critics, and there was no appetite for more of the same. 

Knowing that he was likely to be departing from the series alongside Steven Moffat, Gatiss therefore reverted to his Plan B. He had always wanted to write a story that featured a mash-up of his favoured Victorian period with the Martians. Back in 2013 he had had to fight to bring them back, as Moffat thought them boring - too slow moving and lacking expression.

Moffat agreed to a second Ice Warrior story only if Gatiss could come up with something new, and this included the notion of a female Queen figure.

An obvious inspiration for this story is the third Ice Warrior appearance - The Curse of Peladon. It can be seen as a form of prequel to the Peladon stories, showing how the Martians came to be part of the Federation in the first place. As a bonus for long-term fans, we have a cameo by Alpha Centauri - possibly the same one who will be encountered by the Third Doctor. It is once again voiced by Ysanne Churchman who worked on the earlier pair of stories.

It may even be that the human soldiers will be the descendants of the people of Peladon, or at least be one of the reasons for Earth being such a prominent member of the Federation - one of their number being given the senior assessment role, despite Centauri's low opinion of the planet.

Another inspiration, beyond earlier Doctor Who stories, is the 1964 film Zulu, which starred Michael Caine and Stanley Baker. This provided the Victorian redcoat soldier detail, as well as inspiring some of the foot soldier characters.

NASA finding a message from Victorian explorers on another world was inspired by H.G. Wells' The First Men in the Moon - where modern astronauts find a Union Jack flag and other evidence of a previously unknown Victorian expedition. Gatiss played the inventor Cavor in a BBC 4 adaptation of the book, which had previously been filmed by Ray Harryhausen in the same year Zulu was released.

The guest cast is headed by Anthony Calf, playing Colonel Godsacre. He had featured in the series before - back in 1982 when he had played the squire's son, Charles, in the opening section of The Visitation.

Catchlove - who was inspired by the bullying Flashman character from Tom Brown's Schooldays - is played by Ferdinand Kingsley, who is the son of actor Ben Kingsley. He was concurrently appearing in the Victoria series on ITV, which starred Jenna Coleman as the young monarch.

Iraxxa is performed by Adele Lynch. 

Jackdaw is Ian Beattie, who had appeared alongside Gatiss in Game of Thrones. 

Sgt. Major Peach is played by Glenn Speers. 

Bayo Gbadamosi plays Vincey. The programme came in for some criticism for the casting of a black actor as a Victorian soldier, but Gatiss was able to provide evidence that this was no anachronism.

Richard Ashton plays the Ice Warrior Friday. With a change of mask he played some of the other Ice Warriors, along with regular monster performer Jamie Hill.

We also have a brief cliff-hanging cameo from Michelle Gomez, as the Missy story arc is set up for the conclusion of the series.

Overall, a much more enjoyable Ice Warrior story than the derivative Cold War. We finally see the Warriors on Mars, and learn something more of their culture. The nods to past stories are an added bonus.

Things you might like to know:

• At one point it had been thought that Winston Churchill might feature in this story, as actor Ian McNeice had contacted Gatiss to ask if he could make a return to the series. The Victorian setting put paid to this.
• The setting also precluded Gatiss reusing his Grand Marshal Skaldak character.
• Another idea had been for the story to be set on Peladon, as Gatiss was inspired by the current Brexit referendum in the UK (the entry of the UK into the EU having been an inspiration for the first Peladon story).
• This is the third Ice Warrior story to feature one of their number having crashed their spaceship on Earth. They really are such dreadful pilots that you have to wonder how they ever came to have an Empire...
• The soldiers' portrait of Queen Victoria is an image of the royal as portrayed by Pauline Collins in Tooth and Claw.
• Until William Russell (97) reprised the character of Ian Chesterton in 2022, Ysanne Churchman had been the oldest actor to appear in the revived series, at 92. There is a 43 year gap between appearances for Alpha Centauri - another record broken only by the Great Intelligence (45 years).
• Anthony Calf had also appeared on a Big Finish audio in 2007. It was an Ice Warrior story.

Story 272 (b): The Lie of the Land

In which the Monks have totally subjugated the Earth. Giant statues of them have been set up in every town and city. The Monks have rewritten history to include themselves in every significant event - the truth now being that they visited the Earth in prehistoric times and have been benevolently guiding the human race ever since. Not everyone believes these lies, but security forces - Memory Police - root out anyone who tries to deny this history. They are rounded up and despatched to internment camps, or simply disappear. The Monks are aided in their deception by the Doctor, who regularly broadcasts their propaganda to the world. He was taken away by the invaders, and Bill no longer knows where he is.

She is depressed and isolated, unable to recall events after she had given consent to the Monks at their Pyramid.

She is visited by Nardole, who informs her that he has managed to locate the Doctor. He is being held on a ship in the North Sea off the coast of Scotland. He has arranged for them both to travel out to the prison vessel on a supply boat.

They make the journey and manage to get on board. At one point they had encountered one of the Monks, but it had allowed them to pass. They locate the Doctor's room, but instead of welcoming them he calls for armed guards and then notifies the Monks. he tells Bill that the human race only have themselves to blame for their situation. They deserve subjugation by the Monks, who have brought peace to the planet. When he explains that he has willingly joined with them. Unable to accept this, Bill seizes a weapon and shoots him. he begins to regenerate - but then halts the process. he has only been testing her - to make sure that she is not working under the Monks' influence. He is in league with Nardole and this group of guards as part of an escape plan, and needed Bill to join him. She is angry at his trick, but eventually accepts he felt his actions were necessary, as the Monks control so many peoples' minds. The gun held only blanks, and he has sacrificed a small amount of regeneration energy to test her. They take over the ship and set it on a collision course with the nearby coast. 

They make for the university in Bristol and access the Vault, where Missy is held captive in a glass cage. The Doctor needs her assistance. She has had previous knowledge of the Monks, and may know a way of defeating them. She explains that she encountered them on another planet once, and learned that the only way to beat them was to disrupt their connection with the subjugated population. This is achieved through a psychic link with the person who gave them consent and allowed them in in the first place. She had killed the person who held this position - a young girl whom she had pushed into a volcano. To stop the Monks she states that Bill has to die, as she is their link to the rest of the human race. The Doctor suspects that there is another way - to exploit the link rather than destroy it. He, Bill and Nardole meet up with members of the resistance and head for London, where the Pyramid has settled in the middle of the city. The Doctor deduces that whatever they use to generate their lies is based within it.

They break in, but come under attack by the Monks. They are able to produce shields which protect them from their weapons. To counter the Monks' influence, they use a tape recording of Bill reassuring them over and over again that the Monks are not their friends. Nardole's is damaged, and he attempts to kill the Doctor, and he is forced to knock him out. They manage to reach a central chamber, in which one of the Monks sits with a headset, seemingly oblivious to what is going on around them. This being is generating the false memories to the world.

When the Doctor takes the headset and tries to use it, the Monk fights back and he is stunned. When he comes to, Bill has taken his place. The Monk tries to access her memories in order to exploit them, but she has fixed on the single image of her mother. This is then generated across the globe into everyone's mind. People start to wake up to the truth and turn against the Monks. Realising that they have lost their power, they rapidly depart.

Bill notices that everyone seems to have forgotten all about the Monks very quickly, and the Doctor explains that their massive statues - now all destroyed - contained boosters for their mental influence.

In the Vault, Missy is overcome by emotion as she starts to think about the evil deeds she has committed...

The Lie of the Land was written by Toby Whithouse, and was first broadcast on Saturday 3rd June 2017. It forms the conclusion to a three episode story arc involving the Monks, begun by Steven Moffat with Extremis and continued by Peter Harness with The Pyramid at the End of the World.

Moffat wanted a story in which the villains had already invaded Earth and taken over - something not seen since Day of the Daleks - and in which the Doctor appeared to be colluding with the invaders.

The sort of society which had resulted from this was inspired by George Orwell's 1984 - with Big Brother and the Ministry of Truth, which had "revised" history. 

"Fake news" was very much in the real news, thanks to Donald Trump's 2016 Presidential election campaign.

Right from the beginning, Whithouse planned to open his episode with a Public Information film, like a party political broadcast, presenting a version of history as created by the Monks - but narrated by the Doctor. The Monks would be inserted into artworks, movies, newsreels and even old episodes of Doctor Who.

This idea of aliens inserting themselves into history is hardly original, even for the Series under Moffat, as he had already employed this trick with the Silents (even if there they really were influencing the human race from the beginning, but the imagery is the same).

The fake regeneration trick, to fool the audience into thinking that there's a regeneration coming up, knowing that the lead actor is leaving the series, had also been employed before - by RTD in The Stolen Earth.

Another similarity, again with RTD scripts, are Last of the Time Lords and Turn Left - where we see the companion having to live a depressing existence in a world that has been turned upside down.

It's not just the seeming unoriginality which has gained this episode - and the trilogy overall - a poor reputation with fans. The second and third instalments fail to live up to the promise of Extremis; the motivation of the Monks (quite why they want to invade and what they actually get out of doing so) is never really clear; and the terribly rushed and unsatisfying ending have all added to its unpopularity.

The pacing and structure of the trilogy as a whole are badly thought through.

As far as the guest cast goes, it is a small one, as the episode features primarily the regulars. Michelle Gomez plays a more prominent role in the season from this point on, and her attempted rehabilitation by the Doctor becomes a new story arc.

Two of the resistance members / guards are played by Stewart Wright (Alan) and Solomon Israel (Richard). Jamie Hill once again plays the principal Monks. 

Emma Handy plays the woman arrested by the Memory Police near the start of the episode.

Overall, it's a huge anti-climax. After two episodes of build-up, the Doctor and company wrap everything up in double quick time - easily breaking into the Monk HQ and overturning their rule, and everyone just forgets it all happened. The Monks simply run away. Capaldi and Mackie give great performances - but they are entirely wasted.

Things you might like to know:

• This is one of only eleven stories which do not feature the TARDIS at all.
• The episode was broadcast ten minutes earlier than originally scheduled due to a line-up change for BBC 1 - a special fundraising concert for victims of the Manchester Arena bombing. This was due to be shown the following night, opposite the final of Britain's Got Talent, but ITV moved this to the Saturday to avoid competing with it. The clash with BGT meant very low ratings for this episode - around 3 million overnight - making this the lowest rated episode since Battlefield Part One in McCoy's final season.
• Originally, it had been planned that a scene from the medical soap Casualty - but with a Monk present - might feature.
• It had been intended that an image of Winston Churchill in the Monk HQ chamber would depict him as portrayed by Ian McNeice (Victory of the Daleks etc.), but they decided late in the day on an image of the real one instead. However, it was the McNeice Churchill who appeared in preview copies sent out in advance of broadcast.
• The Monk with the headset in the HQ chamber was originally supposed to be gigantic in stature.
• Some questions. If Bill is so important to the Monks, why isn't she also imprisoned somewhere? What would happen were she to fall ill or have an accident, if her role is so crucial? Why does the Monk on the ship take notice of her, then ignore her? There are only a handful of Monks on Earth, so surely they all know who she is.
• We see a Magpie Electricals shop - the company first introduced in The Idiot's Lantern.

Story 272 (a): The Pyramid at the End of the World

In which the Doctor is called upon once again to take on responsibility as President of Earth. The reason for this is that a seemingly ancient pyramid has just appeared in a disputed region of Turmezistan, at a point where the influence of three super-powers meet - China, Russia and the US. The Doctor becomes involved when the Secretary General of the United Nations comes looking for him, disrupting Bill's latest date with Penny. The Doctor, Bill and Nardole travel to see the building.

They discover that it contains some of the mysterious Monks, one of whom states that they will soon be invited to take over the planet. The Doctor has realised that the location of the pyramid is a deliberate provocation to all three super-powers.

Meanwhile, at a laboratory in the north of England - Agrofuel Research Operations - two scientists are having a bad day. Erica had broken her glasses on leaving her house that morning, and colleague Douglas is seriously hungover. He accidentally administers a much higher dosage of a chemical to some test plants.

The Doctor uses the TARDIS to abduct the military commanders of the three powers, in order that they act together rather than be driven to compete and fight each other.

An American bomber is sent to attack the pyramid, but the Monks are able to disable it and cause it to land nearby. They also pluck a Russian submarine from the ocean and deposit it near the pyramid.

The Monks then invite a delegation inside for talks. The Doctor and his companions are accompanied by the UN Secretary General and the three commanders.

Inside they come to a chamber in which the Monks are operating the machine which generates their simulations. It appears as a mass of glowing threads, each representing a possible outcome.

They show the Doctor's party images of the Earth as it will be in one year's time. It is a lifeless wasteland. The Monks state that they will avert this disaster if they are asked to take over.

When the Secretary General agrees to this and gives consent, he is reduced to dust. He had given consent out of fear.

At the lab, Erica and Douglas see that his accident has created a bacteria which destroys the plants totally. It infects him and he is killed within seconds.

The Doctor deduces that the pyramid is a diversion, to make people assume that the conflict will begin there. He works out that it will commence somewhere else - probably some virus or bacteria in a laboratory, to act so quickly. He has all the research laboratory CCTV cameras disabled, then watches to see which one the Monks switch back on again first - Agrofuel's.

The Doctor and Nardole travel there by TARDIS. As the Doctor meets Erica and decides to incinerate the bacteria by blowing up the lab, Nardole goes back to the TARDIS and suddenly collapses.

Bill is still at the pyramid. The three commanders now give consent for the Monks to take over, but they are also reduced to dust. They had consented through strategy.

The Doctor finds himself trapped in the laboratory as the air filtration system is about to pump the bacteria into the outside world. Nardole cannot help him - and he cannot see the door entry code Erica has given him due to his blindness.

Seeing this on the CCTV at the pyramid, Bill decides to give consent if the Doctor can be given his sight back. Unlike the others her action is accepted, as she has given consent out of love.

The Doctor can see again and he gets out of the laboratory seconds before it explodes.

The Monks now rule the Earth...

The Pyramid at the End of the World was written by Peter Harness, and was first broadcast on Saturday 27th May, 2017.

Harness had last written the Zygon two-parter for the previous series. That had been inspired by current world affairs - namely the radicalisation of young people and proliferation of extremist terrorist organisations. The inspiration this time was political as well - the concerns being raised about the rise of right wing populist leaders, such as Donald Trump. The starting point was: how far would someone go to avert a global disaster - and what if that action turned out to be even worse for the planet in the long run?

The main threat would be a race who appeared to act benign, but had a sinister motive. Having seen mummified bodies discovered in bog land, he decided on a corpse-like species, but coupled this with the imagery of Buddhist monks, synonymous with peace and benevolence, but who could also exhibit martial arts skills.

Steven Moffat liked the idea of these creatures, and decided to devise a whole trilogy of episodes involving them - the first of which was Extremis. Whilst Harness tackled the middle episode, in which the Monks took over the Earth, another writer would take on the final episode in which the threat was defeated.

Needing a unique modus operandi, Harness decided that the Monks would study victim planets and target potential conflict points which they could exploit - arriving as supposed saviours. They would offer their help but really be operating like gangsters with a protection racket.

The writer noticed that there had been a number of "near misses" in history, when a war had almost been triggered by accident - such as a missile going off course, or a computer glitch in a weapons system. The Monks would look for these sorts of occurrences. The threat to Earth would be an obvious one, but the Monks would actually be secretly engineering a different one elsewhere.

Harness restructured his ending when he was told that the Doctor was to be blind going into this episode - providing a handy reason for Bill to accept the Monks' help.

Playing Erica is Rachel Denning (Ghosts), whilst her colleague Douglas is Tony Gardner (Last Tango in Halifax and The Thick Of It - the latter of which also starred Peter Capaldi).

The UN Secretary General is played by Togo Igawa. He had earlier portrayed Dr. Tanizaki in the Torchwood episode Cyberwoman.

The trio of military commanders are: Eben Young (US Colonel Brabbit); Andrew Byron (Russian General Ilya Svyatoslavovich); and Daphne Cheung (Chinese General Xiaolian).

Jamie Hill once again plays the lead Monk, voiced by Tim Bentinck.

Ronke Adekoluejo returns as Penny.

Overall, an impressive-looking story with some fine performances, in which the Monks from last week's episode actually make their move. Their mode of invasion is an interesting one, building on the events of Extremis. Quite why they wish to take over isn't explained. Hopefully that will become clearer in the next instalment. (Clue: it isn't).

Things you might like to know:

• Word wise, this story has the longest ever Doctor Who title to date. It was inspired by Douglas Adams' The Restaurant at the End of the Universe.
• It was originally intended that this would be a UNIT story.
• Harness reuses his fictional central Asian republic of Turmezistan, which had featured in his earlier Zygon story.
• A line of dialogue about terrorism was cut just before broadcast, in consideration of the victims of the Manchester Arena bombing which had taken place only a few days before.
• The cliff-hanger was to have been Bill apparently reduced to dust as well - though it would be revealed in the next episode that the Monks had transported her away.
• The research company was going to be Global Chemicals, as seen in The Green Death.
• The plant enzyme which mutated was to have been DN8 - after the insecticide DN6 which had featured in Planet of Giants.
• Bill's date with Penny goes wrong for the second time, as it is interrupted by the UN Secretary General. In Extremis, it had been the Pope - though that had been in a computer simulation.
• The Doctor's sonic sunglasses reveal Nardole to be 237 years old.
• This episode marks the final time we get to see Capaldi play his electric guitar.
• The Monks use the Doomsday Clock to harass the humans into accepting their rule. Set up by nuclear scientists in 1947, this was designed to show the public how close we were coming to destruction should atomic technology not be properly regulated. Climate change has become a bigger element in recent years. There was a display about this at the recent "Science Fiction Exhibition" at London's Science Museum: