The lawyer Oi sends Conan, Ran, and Kogoro are sent to Izumiya, a long-established fugu restaurant in Shimonoseki, and are hired to find the family's stolen treasured cooking pot. During their investigation, Kogoro comes into contact with a suspicious person in the city at night. Once he's alone, they tell him to mind his own business and attack him. Is his attacker one of the four suspects they questioned during their investigation? Conan visits their restaurants to speak with them again and taste the dishes they pride themselves on.