Five young people take off in a lighter-than-air machine at the Prague Centennial Exhibition. A live-action/animated film based loosely on Jules Verne's novels Two Years' Vacation and The Mysterious Island. The film in Art Nouveau style consists of live-action scenes, generally shot in black and white, as well as hand-drawn, stop-motion, and cutout animation. Various live-action and animated elements are often composited into the same scene.