In the final installment of critically acclaimed Loop trilogy, all of humanity hinges on the greatest escape yet. Luka Kane is dead, executed in front of a crowd of Alts who cheered despite the fact that the truth of their oppressive leaders had been revealed to them. But one Alt, Chester "Chilly" Beckett, did not celebrate; his eyes have been opened to the truth. Luka's corpse is dragged away, but Chester remains determined to find out what is going on in the Laboratory on the 65th floor. There, he finds three subjects tortured in an attempt to extract a regeneration formula... and one of the subjects is, impossibly, a face he never thought he'd seen again. A bold escape sets in motion a race against time as Happy's plans to release planet-eating nano-bots into the world draw nearer. The Loop team must reassemble, survive Happy's final attempts to rid the world of the rebels, and figure out how to halt the apocalypse before humanity is destroyed.