Two dead in the dense fog of autumnal Lake Constance. Markus Söckle, engineer on a Lake Constance ferry, drowned – but before that he received a massive hit on the head from a stranger. On the other hand, it is known who killed Beat Schmeisser on another lake shore: Klara Blum's Swiss colleague Matteo Lüthi. He had been looking for Schmeisser and shot him in pursuit. In self-defense, claims Lüthi. It's just stupid that there's neither a weapon nor traces of smoke on the dead man. Klara Blum investigates the death.
Was Matteo Lüthi actually in oneSelf-defence situation or did he shoot prematurely because he still had an unfinished business with the criminal Schmeisser because of a kidnapping case? During the investigation into the Markus Söckle case, Kai Perlmann made a surprising discovery: the young woman with whom Söckle was last seen has disappeared without a trace. Her father is a wealthy builder and Beat Schmeisser has been spotted around her. Schmeisser may have been involved in a kidnapping again. Anna's parents refuse to cooperate with the commissioners. But time is pressing...