Caden Bosch is navigating his sophomore year. He's mentally adrift, in a literal way: when he's not in the real world, he is on an ever-changing ship sailing toward the Marianas Trench, off to explore the deepest part of it. The captain and the captain's parrot demand opposing things from him. In the real world, people are noticing his odd behaviors, his paranoia. 
 This book is terrifying, not in the "scary clown" nightmare sense but the unflinching descent into mental illness sense. The Author's Note at the end says that a lot is based on the experiences of Shusterman's son in the throes of a schizoaffective disorder. Caden is trapped in his delusions and is confused by them in his moments of lucidity; the reader is right alongside him, powerless to help or mitigate or even understand. 
 Great read. I'll be surprised if it's not on the Printz list come January.