The decapitated Celestial head that's the home to Knowhere just woke up and warned everyone of a massive threat to the universe. That's good (the warning.) Too bad the Inhumans' big bomb already went off. That's bad. But Black Bolt and Vulcan died in the explosion. That's good! But it also tore a massive hole in the fabric of the universe. That's bad.
While Warlock, Gamora on his heels, seeks a solution, what's left of the team - Rocket, Groot, Drax, Major Victory, and Phyla-Vell - teleport aboard the Inhumans' big ship. In theory, they want to make sure there's no second bomb, but it's mostly the Guardians berating the Inhumans for being idiots. Fair.
This much deserved finger-pointing is interrupted by massive tentacles emerging from the Fault to reel in the city-ship. While the Inhumans and some of the Guardians try to fend off the invaders, Rocket, Crystal, and Groot stick with Maximus the Mad, to find some way. But really, it's just Maximus and Groot talking it out, while Crystal and Rocket watch. All we see Groot saying is, "I am Groot," but Maximus insists that's because of the hardened formation of Groot's larynx, and you need to listen to the 'breeze beneath it.' Rocket and Crystal agree Maximus is as crazy as a bag of spanners, which is not an insult that makes much sense, but hell, it's been a long day for everyone.
Maximus and Groot somehow unmake the creature by uncreating its reality and imposing their own. Whatever that means, that's good! The Fault is still growing and the ship lost enough velocity it's falling into the Fault. That's bad. A bunch of templeships of the Universal Church of Truth arrive! That's bad. Phyla investigates and finds Adam Warlock preparing a big spell to arrest the Fault's growth by grafting their timeline to an inert future. That's. . .good? The spell is powered by the faith generators of the Church of Truth, and the engines are powered by the belief of their followers, burning them out in the process. That's bad.
Warlock casts his spell, the Fault stops growing, Maximus looks very confused as Crystal hugs him, Adam takes a moment to appreciate his act, while aware of the dangers, and then Phyla stabs him through the chest with her sword. She made a deal with Oblivion to get Moondragon back, and it involved killing the Avatar of Life at the right moment. Gamora objects, they fight, Phyla gets stabbed in the chest. See how you like it.
Gamora rushes to Adam's side, but Warlock's not home. Instead it's the Magus, but the inert timeline Warlock used was the one where he turns purple. Gamora bemoans Warlock dooming himself to save the universe - ignoring that the universe ain't gonna be in great shape with this putz on the loose - and Magus snaps her neck and tosses her body into space. This outcome would subsequently appear to be averted - time travel shenanigans - but that would be a fakeout, too.
{5th longbox, 38th comic. Guardians of the Galaxy (vol. 2) #17, by Dan Abnett and Andy Lanning (writers), Brad Walker (penciler), Victor Olazaba and Scott Hanna (inkers), Jay David Ramos (colorist), Joe Caramagna (letterer)}