The library employee Peter Thies admits the murder of the Susanne Richter. Although Thies has accurate perpetrator knowledge and one of the two DNA traces at the crime scene comes from him, Nina Petersen has doubts about his confession.
A young woman's body, cast in concrete, is discovered during the renovation of a house. It is the body of Klara Grist, a childhood friend of Nina Petersen. Klara disappeared without a trace in 1996 at the age of 17.