Conan, Ran, and Kogoro are on their way to a Yōko concert when Kogoro discovers he lost his ticket. He overhears a woman named Masayo on the payphone and her situation about a friend who is unable to go to the concert because of a cold. Kogoro asks her for the spare ticket and she accepts as long as Kogoro drives her to her house to pick up her sister, but they find Masayo's sister dead.