Munich at night: Robert Susmeit, a 16-year-old teenager who is jealously obsessed with his mother Hilde, traces her and her latest lover at a mundane apartment building where he kills the man in the heat of the moment at a swimming pool. His fatal outburst is secretly witnessed by Moni Dingeldey, a girl of the same age as his. Fascinated by the shaken and devastated strange boy who she hopes to be a soul-mate, she hides Robert in her mother's apartment. Meanwhile, a crowd of policemen and reporters frantically comb through the building in search a murderer whose identity is known only to Robert's parents who are searching as well...