Two anglers discover a pile of corpses in a field near the polish border. The unimaginably high number of skeletons and animal carcasses leads the police to suspect a serial killer who has apparently been killing undetected for decades. Local detective inspector Roland Voit is assigned to support the large LKA contingent in the Oderbruch. His former childhood sweetheart, former policewoman Maggie Kring, is also called to her home town of Krewlow. After years of silence, Maggie and Roland are anything but impartial. Maggie is following her own investigations. She left Krewlow in 1997 after her brother became a victim of the historic Oder flood at the age of 17. The ex-policewoman doubts everything she knows - including the death of her brother Kai.

Poland, summer 1990: ten-year-old Kai has been taken to safety by his mother Minna to stay with Polish friends. His father Arthur wants to kill him because he suspects that Kai has a sinister tendency. His sister Maggie fearlessly stands up for Kai and has to protect him from other children. A fight breaks out on the way to school, in which the leader Conradi is seriously injured and Maggie is knocked unconscious. Kai swears to his father that he will never tell Maggie the truth about himself. A sinister man also knows that the introverted boy is special. He seeks Kai out and offers him the chance to live with his "real" family.

Maggie Kring and Kai travel to the Carpathian Mountains. There, the siblings try to find out who the mysterious man is who came to the Oderbruch with their father in 1947 as a former war deserter. In Romania, however, they initially come up against a wall of silence. Roland Voit follows Maggie's tracks, even though he has been suspended from the case. He discovers the body of a dead teenager in the forest hut. When his Polish colleague Stanislaw Zajak tracks him down, Voit has no choice but to play his cards close to his chest. Zajak entrusts him with a theory about similar unsolved and mysterious murders in other countries and forces Voit to help find Kai.