Kogoro brings Conan and Ran to Kusumi Machinery, a robot factory. Kogoro has been hired by President Kusumi to determine which of his employees Tanizaki, Horiuchi, and Isshiki have been leaking parts to Myojo Technics. Kogoro believes Tanizaki, who met with Makita of Myojo Technics, is responsible. That night, Kogoro, Conan, and Ran hide in the factory to catch the thief in the act, but Tanizaki`s body is found in the storeroom where a gas leak occurred.