Yoko Okino comes to the Mouri Detective Agency and talks about an incident that happened at a villa. Instead of Kogoro, who is holed up in the bathroom and does not come out, Kennori Wakita of Iroha Sushi and Conan are assigned to the case. Producer Wanya Fuejima of Nippei TV, who was at the villa with Yoko at the time, informs them of a sister, Baba Houka, who disappeared several years ago and is believed to be related to the case. Houka's husband, Baba Kankou, Kankou's younger brother, Baba Fugo, and his wife, Baba Himi, were childhood friends who had been together with Houka for a long time. Hoka was Kankou's wife, Fengo's first love, and Himi's best friend...