Shortly before closing time, a jeweler in Stuttgart is robbed. He himself is injured and his customer dies while trying to escape. The robbers' actions are similar to an attack from the previous year and so the Maslov and Ellinger families, who are related by marriage, become the focus of Thorsten Lannert and Sebastian Bootz's investigation. The adult members of the family have a lot of experience in deflecting police inquiries and providing alibis. That leaves 13-year-old David, who is housed in a youth home. The detectives suspect that the teenager, who is underage, was employed as a guard during the attack. The social worker Annarosa, who looks after him, defends the boy with complete conviction and in principle doesn't make any effort to support the police; she doesn't think much of state rules.