21-year-old Mike Schwarz is found dead in the Krüger family's pool on his birthday: he was drowned.

Patrol colleagues Carlotta Heffler and Tom Landwehr are called to a disturbance; loud music is coming from the Köpenick Rowing Club. The two of them are presented with a gruesome sight.

Taxi driver Yvonne Grabowski is shot. At the crime scene, the perpetrator pretends to be a passenger and witness. Robert realizes too late who he is dealing with. The perpetrator manages to escape.