In a zany futuristic setting, a comical action-packed adventure unfolds. Shinnosuke's would-be bride-to-be, Tamiko Kaneari, arrives from the future using a time machine. She reveals that her father, Masuzo Kaneari, has imprisoned the adult Shinnosuke in a dystopian future and requires the help of his 5-year-old self to set him free. Together with Shinnosuke and the Kasukabe Defense Forces, they journey to Neotokio, a sprawling metropolis ruled by Masuzo Kaneari, the influential president of Kaneari Electric, to confront their daunting destiny.