Young Nikolay is a national boxing champion. On a picnic, he meets Vanya and falls in love with her. They have a lunch in the restaurant and when a brawl erupts there, Vanya leaves. Nikolay tries to catch up with her in a car, but has an accident. The uncle of his friend offers to pay for repairs of a car if he will agree to act as a courier in foreign currency smuggling deal. Nikolay agrees to take along a box of matches. The uncle tells him that he will receive as many dollars as there are matchsticks in the box. Nikolay is due to leave for Paris to compete in the world championships. During the journey, his coach confiscates the box, thinking that the athlete is smoking. Nikolay has to explain everything. The coach contacts the Bulgarian police who identify the box of matches as a container used by spies to pass on intelligence message. Nikolay agrees to go through with the mission assigned to him by the spies to penetrate their network. On their way to Bulgaria, two friends promise to come forward as witnesses and testify in his favor when he is tried for spying. The two do appear as witnesses... in whose presence the marriage between Vanya and Nikolay is solemnized.