Before the eyes of Hubert and Staller, Klaus Böttcher jumps to his death from a bridge. Shortly before, the family man had been at the police station to give a statement. However, after receiving a text message, Böttcher quickly left again. Was the man driven to his death by this message? An unknown sender apparently threatened to harm Böttcher's young child shortly before his act of desperation. While the police are searching for the sender of the threatening email, Hubert and Staller have another problem.