Five young friends discover a network of time travelling tunnels that take them to different eras in Japan. Forty years later, Satoshi runs the traditional paper mill of the village and struggles to make ends meet. Strange things start to happen when a nefarious developer with connections to the tunnels swoops in and makes the region a tourist spot. Satoshi and friends are called into action as guardians of the tunnels when the developer discovers a samurai who wanders in from another era.