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.

The large LKA contingent is searching for a serial killer in Krewlow and hopes to get a clue from the only survivor found on the pile of corpses. However, the seriously injured man is unresponsive. For the village doctor Frank Seeger, it is clear that "Pulver-Paul" is behind the bloody deeds. The gun-crazy hermit is holed up on his farm and obsessively believes he has to defend himself against overpowering enemies. When Roland Voit and Stanislaw Zajak want to interrogate him, a life-threatening confrontation ensues. Meanwhile, Maggie is staying with Adrian Demko, her childhood friend who is in a wheelchair. She is convinced that the key to the Oderbruch serial murders lies in their shared past.

Maggie was right: Kai is alive! The siblings hide together in the abandoned forest hut. Kai's confession that he has many people on his conscience upsets Maggie just as much as his seemingly unimaginable explanation. After an attempted assassination, they are both in constant danger. Maggie turns to Voit - without telling him that her brother is alive or revealing anything about his involvement in the series of crimes. Meanwhile, Voit's colleague Zajak deciphers a mysterious document left behind by the survivor of the pile of corpses before his death. On the Polish side, schoolgirl Ilona makes an eerie discovery. Something is wrong at the secluded boarding school for street children and runaways. Blood donations are compulsory, girls are disappearing and sinister men are coming and going.