Shortly after the end of the war, Kindaichi Kōsuke, visiting a remote island in the Seto Inland Sea, arrives at the powerful Kitō family on the island guided by the monk Ryouzen. There, Kindaichi encounters a beautiful woman named Sanae and encounters three sisters with unconventional and outlandish appearances that don't quite fit the island's atmosphere. And then, one evening, the youngest sister disappears... Kindaichi Kōsuke is rebooted into action!