Fire on board. At the deepest point of Lake Constance, millionaire heiress Marita Schiller is forced to flee her yacht wearing a life jacket. Along with her boat, an expensive piece of jewelry she had kept in an onboard safe also goes down with it.

A shocking discovery at the school camp. Lea, a 17-year-old classmate of Niklas, is found dead, floating on the shore of Lake Constance. Suspicion quickly falls on teacher Andreas Ritter, who had been supervising the class alone—a violation of the rules.

Does Nele have a new admirer? Her mother suspects so and sets her lodger and colleague Jakob Frings on her own daughter. But Nele is currently trying to find out who is responsible for Niko Schöller's death.