After being raped in the hotel room where she stayed during a scientific conference, psychiatrist Emma Stein no longer leaves the house. She is the only one of several victims of a psychopathic maniac left alive and is afraid that the criminal will overtake her again to complete his terrible business. Driven to the point of paranoia, Emma feels safe only in her small mansion on the outskirts of Berlin, but only until one day the postman asks her to accept a parcel for a neighbor. Men whose name is unfamiliar to her and whom she has never seen, although she has lived on this street for many years...