A teacher about to start his first position moves into a well-worn apartment with a mysterious, locked room. He realizes someone else is using the place: A young woman claiming the previous tenant allowed her to stay as she pleases. An official letter expresses doubts about his loyalty to the German constitution and summons him to explain his political stance in an interview prior to beginning teaching. The teacher suspects he's being spied on: People in the neighborhood act suspicious. He breaks open the locked room and is surprised to find it empty. A newspaper article about terrorist bearing an uncanny resemblance to the teacher makes him conclude he's mistaken for the terrorist who has died. The movie's title refers to the supposed mistaken identity: "That dead man is me". He finds the previous tenant in the apartment removing a large sum of cash hidden in the empty room. In the end he joins this man on a trip in his convertible.
