With an acoustic sense on the trail of evil - a crime novel that captures the melody of the North Sea. Chief Inspector Flottmann has transferred from the Rhineland to Northern Germany to find some peace. However, that doesn't last long. A series of kidnappings has the region on edge, and the perpetrators are extremely brutal. When the investigation stalls, Flottmann resorts to unusual means: he seeks help from Leon Gerber, a musician with highly sensitive hearing. Can he provide the crucial clue?.