Libby Marchmont lives a privileged life on a drowned Earth. As the daughter of City’s only doctor she has it all, including the opportunity to assist her father in his surgeries to create nautilus men — the divers of the deep that keep society supplied with food and tools from the Time Before.
But when her father secretly performs nautilus surgery on a lowly and infuriating reamer boy named Cosimo, Libby knows something is wrong. And when she and Cosimo are forced to flee, leaving Libby’s father murdered on a dark pier, her life is turned upside down.
Stranded in the middle of the sea with a boy she hates, Libby must survive long enough to uncover the truth: the tides are rising again and it will take more than nautilus men to save the world this time.