The brutal cop Volker caused the death of Soufiane Hamid, who fell from the balcony during a raid. Five years later, officer Volker dies in the same way as Soufiane, but it is suspected that someone apparently assisted Volker.

Martin Jesch kills police officer Gerry Engler with an axe, whose head is found in a park with a head full of blood. Engler had killed a young man with an iron five years ago.

Wilder and Kägi search for headmistress Patrizia Schellenberg, whom the serial criminal has chosen as the third victim. Patrizia allegedly let drug courier Lola Mbeki freeze to death.

Aeby says she met the supposed serial killer a few years ago. During this meeting, Aeby discussed the cases about Volker, Schellenberg and Engler with him.

Rosa Wilder drives with prosecutor Mettler to the place where another body has been found. Mettler gets anxious when forensic experts discover fingerprints.

Rosa, Kägi and Mettler go to Martin's house and find poor Max Zimmermann unconscious. However, Mettler notices Martin's footprints in the snow and follows them.