The body of a young, athletic man is floating lifelessly in the lake. When Nele and Paul pull the surfer—who is already severely hypothermic—from the water, it's too late to save him. Daniel Dellbrück was the victim of deliberate blows—with a paddle?

What starts out as a routine procedure suddenly turns into a murder case. The animal spotted floating in Lake Constance turns out to be a corpse dressed in a fur costume and wearing a carved wooden mask. Achim Tilger, the deceased, had just suffered an unprecedented business collapse.

Within the walls of the Oberzell Monastery on the island of Reichenau, stressed-out city dwellers often seek relaxation and contemplation. Bestselling author Armin König had also checked in here. But why?