While Chief Detective Ann Kathrin Klaasen, with Commissioner Frank Weller and Commissioner Rubert, is still busy solving the murder of a young girl found in the moor, Gundula Müller's twin babies disappear. Gundula's ex-husband Wolfgang Müller is suspected behind it. Her new boyfriend Thomas Schacht is so angry that he drags him into the moor, so he dies. Schacht is arrested. The investigators continue to investigate the dead girl, identified as Jule Freitag, who lived in an institution. The body of another young girl of the institution is also found in the moor. The evidence shows that Dr. Alexander Ollenhauer, who is in charge, has raped the girls. The first case of the missing girls of the institution occurred 8 years ago. The victim is Tanja Stendahl, who has a twin sister Frieda Stendahl. Klaasen recognizes Frieda Stendahl as the new forensic assistant Frauke Thanner with whom Rupert has started an affair. When Rupert hears babies' noises at Thanner's, she knocks him down and ties him up. When confronted by the investigators, she confesses since no one could testify against Dr. Ollenhauer, she killed those girls to prevent them from suffering. She also confesses since she wanted a family of her own, she first took the babies and then hold Rupert captive to be her husband. She is arrested and the babies are rescued.