The authorities expect the case of Friedel Walter, alias "Dr. Mueller," to be a straightforward one: he was working as a doctor without proper credentials under a false name. But Mehlin, the man in charge of his case, knows that there is more to the story.
Valuable PVC produced in the GDR is being smuggled across the sector boundaries in Berlin to supply Western chemical companies. Officer Schubert begins to investigate the case, but he is at a loss for leads when all the production and export records appear to be in order.
Manfred Falk is an experienced race car driver and member of a racing collective in Eisenach. While competing in West Germany, the beautiful Manuela convinces him to leave his girlfriend Inge and his friends at the collective behind in order to join the South American Alvarez racing company.