Shinnosuke Nohara, and his sister Himawari, have a fight over a plate of custard. Suddenly, two mysterious men appear in green clothing and hats bearing sunflower emblems (Himawari means “sunflower” in Japanese). They refer to Shin-chan’s sister as a princess, and pass a paper to Shin-chan who signs it without hesitating which actually had that he would give Himawari to their planet as a princess. The Nohara family is promptly abducted to a UFO in a scene that draws some visual concepts from the “Phantom Zone” jail, used in the Superman motion picture series.
The Nohara family (father, mother, brother, sister, and their dog) all travel aboard the UFO to the “Himawari planet” on a mysterious and important mission that affects Earth, and may decide the fate of peace across the entire universe.