The body of a young woman, Vera Grimm (Victoria Hauer), washes up on the shores of Lake Constance bringing Micha Oberländer and Luisa Hoffmann to the scene. Forensic pathologist Egger (Stefan Pohl) coincidentally saw the young woman on the morning of her death with a little boy, who is now missing. When the detectives visit the murdered woman's sister, it quickly becomes clear that the father of the family, Andy Löffler (Andreas Kiendl), has been caught up in his criminal past. The missing boy is his son Augustin, who was kidnapped by one of his father's accomplices in order to trade him for the stolen "Medusa", a fine gold bust worth millions. 

Luisa Hoffmann's dangerous ex Antonio Zübert (Luka Dimić), of all people, can provide clues to the perpetrator, but only on condition that their daughter Liv will visit him in prison. Hoffmann is faced with a dilemma: Should she give in or risk the life of the kidnapped Augustin if she refuses?