The Governor of Tokyo, Yuichiro Asakura, receives a threatening letter the day before the opening of Touto Line, a new train line for the Tokyo Metro. During the opening ceremony of the line, Conan Edogawa and the Detective Boys are driven by Professor Agasa and pass under the Touto Line. Conan, having heard about the threatening letter, notices explosives connected to the Touto railway; Using his original voice to inform the police as Shinichi Kudo, he is able to stop the train and divert traffic away from the explosives preventing any deaths.