When a man is found slain in a run-down tenement, Gregor Reinhardt investigates for Berlin’s civilian police force, while having to answer to the Allied powers ruling different parts of the city in 1947. After discovering a serial killer is on the loose and that one of the victims was the brother of a Nazi scientist, Reinhardt realises his hunt could cost him everything as he comes under scrutiny from a group of Germans wanting to continue the war and the Soviets, while racing against time to catch a killer trying to avenge past wrongs.