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.

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.

SoKo Krewlow is on the hunt for Marek Gorski, who has gone into hiding, but a deadly trap awaits the officers in his trailer. Meanwhile, mysterious men have taken control of the Polish boarding school. Pupil Ilona fears for her life. On the run, she discovers a mysterious prisoner. He promises to help if Ilona frees him. Roland Voit is certain: there must be more than one perpetrator! When Gorski demands money from Demko for his escape, the police team drives to a remote drop-off point. However, Maggie Kring and Voit see through the ruse. A fight for life and death begins with the "Great Hunter", in which Maggie outgrows herself - and makes a fatal decision.