A New York Times bestselling series
A USA TODAY bestselling series
A California Young Reader Medalwinning series

Sophie battles the rebelsand recovers dark memories from her pastin this jaw-dropping fourth book in the bestselling Keeper of the Lost Cities series.

Sophie Foster is on the runbut at least shes not alone.

Her closest friends from the Lost Cities have gone with her to join the Black Swan. They still have doubts about the shadowy organization, but the only way to find answers is to start working with them. And as they settle into their new lives, they uncover secrets bigger than anything theyd imagined.

But their enemies are far from done, and unleash a terrifying plague that threatens the safety of an entire species. Sophie and her friends fight with everything they havewith new allies joining thembut every choice has consequences. And trusting the wrong person could prove deadly.

In this game-changing fourth book in the Keeper of the Lost Cities series, Sophie must question everything to find a truth that will either save her worldor shatter it.