If you take it at face value, the premise behind most Mario games is pretty ridiculous. You'd think that after having been kidnapped by nefarious forces five hundred times, Princess Peach's chancellors would bolt the door to her chamber, build a moat around it, and post mercenaries around the perimeter. But no. She always gets jacked while out on one of her adventures, and it's always up to Mario to get her ass out of the oven. What a quasi-racist caricature is doing in a kingdom full of mushroom people is a whole other question entirely, but I won't get into it. Seriously, though, when will this get old? How long will we continue swallowing this ridiculous narrative, hook, line, and sinker?
The answer: As long as they keep making Paper Mario games, they can do it forever. Just like its predecessor, Paper Mario: The Thousand-Year Door plays with the absurdity of the Mario formula in marvelous ways. It makes fun of itself relentlessly, yet still manages to be earnest when it matters, and the gameplay around which it's built takes the best elements of the Mario games' trademark simplicity, and constructs out of them a compelling, engrossing RPG.
In Another Castle
Rote as it is to do so, Paper Mario: The Thousand-Year Door's story bears mention. One day, Princess Peach decided to go on an expedition, one part of which brought her to a seedy burg called Rogueport. Bewitched by legends of treasure buried deep within the city's ancient foundations, she decided to make her stay there an extended one. As turns out, however, other -- decidedly nefarious -- forces were after the same thing.
Do the math: she gets kidnapped, and Mario comes to the rescue. How will he save her? By collecting stars, of course - ones made out of crystal. A treasure map that Peach sent him (a magic one, too) points him in the direction of each. So yes; Mario has to acquire a series of stars before he is able to rescue Peach, and take on the do-badders that stole her. But he gets help a little help from his friends, along the way.
Given the tone of the above passage, it's probably hard for you to believe that I'm actually very delighted by Paper Mario: The Thousand-Year Door. All the clichés present in it are thrown at you with the utmost cleverness, and the quality of the writing is typical for what Nintendo's localization team produces. Basically, you'll actually want to talk to the myriad characters that populate the colorful worlds. Inane as what they have to say usually is, it's also often clever and funny. Maybe it has something to do with that Nintendo magic that everyone is always talking about, but there's definitely something here for everyone, even if they may normally think themselves above something so saccharine.