A seemingly blunt man named Yasushi lives on Sanagi(pupa) Island in the Seto Inland Sea, which is famous as a cat island. One day, Yasushi meets a woman named Hanako who wanders around the island soaking wet. She asks him to find a "bag" that she had lost after dropping it in the sea. Chika, a childhood friend of Yasushi, and her husband Kiyoshi, who was returning home at the time, happen to find a mysterious round capsule-shaped "bag" on the beach. What they find inside is an unbelievably large wad of cash... A science fiction fantasy about the past, present, and future that takes place in a traditional Japanese island landscape.