Conan, Ayumi, Mitsuhiko, and Genta go out for a drive in Professor Agasa's car. On their way home, they pass a building with an unnaturally flickering light in a third-story office. Deciphering the Morse code for SOS, they head to the office, where they find a tied up motorcycle deliveryman. He claims a bomb has been planted in the room, and the hurriedly flee the scene.