In this dark, brilliant sequel to Incarceron (2010), worlds within worlds collide to mutual destruction—or, maybe, rebirth. Finn has finally Escaped the sentient prison world with aid from the Warden's daughter, Claudia, but escape hardly means freedom. As they struggle to negotiate the poisonous intrigue of the Realm and unlock Incarceron's secrets, their allies still trapped Inside seek a rumored artifact of the legendary Sapphique. For Incarceron has gone insane and is determined to Escape itself... Breathtaking worldbuilding describes two very different dystopian dimensions with surreal splendor and cruel artifice. The price exacted upon even the humblest characters is portrayed unflinchingly; yet the selfishness, deception and treachery of every protagonist does not prevent them from being painfully sympathetic and real. Even as the steadily ratcheting certainty of impending catastrophe keeps the pages turning, the sheer richness of the evocative descriptions demands that every sentence be savored. No conventional tidy ending is offered; the bleak conclusion glimmers from only the faint hope gained by revealing the truth. Not for everyone; but for those who can appreciate the interplaying reflections of lies, myths and memory, a modern masterpiece. (Science fiction. YA)