This is fucking cracktastic and I love it. It's part 1 of a duology (hurrah for fantasy not being at trilogy), the follow-up being Sapphique, and although it kind of leaves you hanging it's still a fairly effective emotional arc.
So the premise is this: Incarceron, right, is a sentient prison. How awesome is that? About 150 years before the book begins, all the social undesirables and criminals were dumped in there, and the prison was supposed to provide a paradise for them and help guide them towards enlightenment. But, of course, it all goes horribly wrong (who came up with that plan, anyway, had they never read a single piece of sci-fi?) and the prison has, instead, created a hell from which nobody can escape. Outside Incarceron, society has stagnated into a sort of rigidly imposed faux 18th century called 'The Era'.
Again, we have two parallel plots that don't so much come together as weave in and out of each other: Finn is a prisoner who dreams of the outside world, Claudia is the daughter of the prison Warden, trapped in a web of politics, intrigue and arranged marriages.
This is a book with big ideas, complicated characters and a fast-moving plot. It's everything I really love about fantasy with none of the stuff I really hate, and all in about 300 pages breathless pages. I genuinely don't know how the author fit it all in. But there's backstory, actual story, adventure, betrayal, horror, worldbuilding, subtlety, drama, discovery, meditations on censorship, authority and justice ... you name it, it's there.
And the prison itself is terrifying. Terrifying and weirdly heartbreaking. Like its Warden.
Can you even dream how it is to live for ever trapped in your own mind, watching only the creatures that inhabit it? They made me powerful and they made me flawed.