Several months after Nutrexo's downfall, Andi plunges into a new mission: investigating a dietary supplement with unusual, potentially-dangerous side effects. Cyrus wants to help, but he's hopelessly distracted by the painful secret he's been hiding about his older brother. He can't bring himself to tell anyone what really happened that night. Not even Andi.

Meanwhile, Roya is vacationing on a remote island when she makes a chilling discovery. A human skeleton-and near it, a rusty iron key. Can the mysterious girl Roya glimpsed on the bluffs help her piece together some answers? Or will she drag her down into the dark undercurrents flowing beneath them?

This sweeping sequel to When We Vanished takes the reader on a journey through time and place, from a 1970s island commune to a present-day corporate apple orchard, as it explores the question of just how far we'll go to help the people we love.