In a mysterious vault below the mountain of corpses, the police units not only discover more bones, but also a water glass with leeches. The seemingly insignificant find awakens the memory of Kai, Maggie's missing brother, in Roland Voit and Maggie Kring. Kai was an extraordinary, mysterious boy. Maggie simply cannot and does not want to believe that he is no longer alive and now hopes to have found proof of this. She asks Adrian Demko for support. Adrian has been in a wheelchair since a terrible accident in her youth, in which an unexploded bomb from the Second World War exploded. He instructs his carer Marek Gorski to accompany Maggie on a trip across the border to Poland. The trail leads the two to a mysterious building in the border area - there an assassination attempt is carried out on Maggie.