The East German authorities are calling the West German Police for assistance on a case. The body of a boy was found at a Truck Stop near Leipzig. The boy wears shoes made in West Germany. Some time later the assistance call is withdrawn. Phoning his colleague in East Berlin, a man he worked together with in the past, investigator Paul Trimmel in Hamburg is told: "There is no work for you here." But Trimmel investigates on his own. He finds out that the wealthy Erich Landsberger is the illegitimate father of the dead kid. Landsberger and his other son have moved to Frankfurt. Trimmel pays him a visit there. The man is of no great help for him, but Trimmel gets an unexpected clue from Landsberger's little son. He has to go to Leipzig himself to find out more. So he leaves the Transit Route near the city, pretending his car broke down, takes a Taxi and goes looking for Eva Billsing, the dead boy's mother. She is not home when Trimmel arrives. The next day Trimmel encounters Eva's boyfriend Peter Klaus, who works for the East German Police, and talks him into letting him have a word with Eva. At least Klaus gives in to Trimmel and the things Eva tells him help solve the case.