Underwater, Fin is supremely competent. On land, not so much. She has trouble making friends. Trouble with her family. Trouble with her ex-husband, and trouble managing her career. But her problems really take off the day of the first accident...Two divers are freediving, practicing for a deep dive. Fin will be filming their feat for the Cayman Island oceanographic institute where she's chief underwater photographer.One diver doesn't return after 4 minutes underwater. Fin dives down and rescues him. When he revives, he tells a wild tale of an unknown diver holding him below. Fin and the other diver chalk it up to an oxygen deprived hallucination.Until the next accident. And the next.Finally, Fin realizes someone is targeting her family and the institute's employees. And she figures since she's the one taking the blame for all the incidents, it's up to her to find the killer before one more person she loves doesn't make it back.