The basic premise: A retired bus driver fulfills his lifelong dream of providing an extended "voyage surprise" (the title is translated as "Mystery Tour") for unsuspecting vacationers. They soon realize, while riding in the old man's home-made bus, that he hasn't bothered to plan any kind of itinerary. As a result, they end up in completely preposterous situations, of course. Voyage surprise!

To teach a lesson to his young wife who dreams of the famous "voiceless singer", a husband enters a radio station and manages to make people appreciate his voice.