The felon Hendrik Larsen goes on the net for Ben and Semir, but his accomplices can escape. Larsen's arrest is also important because it is the last hope for a terminally ill child: A bone marrow donation from the multiple killer would save Paula, who has leukemia. But it doesn't come to that. Larsen uses the surgery date to flee and threatens to radioactively irradiate the whole of Cologne unless he receives the requested 25 million euros. Ben and Semir are in a quandary because they have to hold Larsen alive in order to save not only the city but also Paula. The dangerous sociopath takes advantage of this fact and plays a perfidious game with the desperate cops.