On class cleaning day, Rantaro, Kirimaru and Shinbei decide skip cleaning and sneak out. On their way out, a Black Hole suddenly opens up on the floor, and the three fall into a world of darkness. Beyond the darkness they meet Miss Swan, an expert space tour guide. The three go on a tour to see the most spectacular view of the universe on her space ship “Swan”. The tour takes them through the life of a star, star clusters and nebulas, and finally to the Black Hole, but as always, trouble awaits them! Can the three of them return to home safely!?