An unknown man apparently threw himself in front of a train and was run over. However, coroner Dr. Graf does not believe in suicide, and when Moser and Rex find suspicious traces near the railway embankment, it is clear: The man was already dead before the accident. Neither the wife of the dead Gerti nor his lover Irene can show an alibi. Only when Kunert, the mechanic of an illegal car repair shop, finds traces of blood on the expensive car of the young Alexander Prince does Moser track down the criminal. But the arrest is thwarted, the perpetrator can flee...