A missing child. A desperate father. A terrible secret. Guido T has already confessed to two horrific child murders and led Berlin police to the bodies. The police are sure he is also the murderer of six-year-old Max, who disappeared without a trace a year ago. But now the killer is staying silent. The investigators have no reliable evidence, so Max's parents have no certainty and are unable to say goodbye to their son. Everything changes when one investigator makes an unbelievable offer: he can place Max's father, as a fake patient, inside the maximum security psychiatric hospital where Guido T is imprisoned. Max's father agrees. He plans to force the child killer into a confession. Because nothing is worse than uncertainty. Or so he thinks...