Investigating a heinous crime committed outside his jurisdiction, Guido Brunetti wants to know more about two young American women injured in a boating accident with two young Italian men. If it was just an accident, why did the Italians flee the hospital? As Brunetti and Claudia Griffoni investigate, they discover that one of the young men is connected to sinister nighttime activities in the Laguna. To get to the bottom of what proves to be a gut-wrenching case—his 30th, after Trace Elements—Brunetti will need allies, but can he trust them?