Not far from Prague, a drunk driver of the car with West German front license plate comes into collision with a girl hitchhiker. The police detains the offender - the business agent Grandner. In West Berlin, in his home firm Tanass, it makes a stir. Tanass is in fact the branch office of the American secret service and Grandner was one of the agents. Nobody suspects that Peter Halva (Radovan Lukavský), a senior director, Czech émigré, working in the firm for ten years, is a member of the Czechoslovak espionage.