Kogoro takes Conan and Ran to the Beppu hot springs in Oita Prefecture. Kogoro's true purpose is to find Manami Nakadai, the missing daughter of Nakadai Electric's president. It's highly probable that Manami came to Beppu to see her ex-boyfriend, Hiroyuki Hayami. Kogoro is able to find Manami, but she is then kidnapped. Meanwhile, Detective Miwako Sato and the police are pursuing an armed robber in Oita Prefecture.