While playing at the park, Conan, Genta, Mitsuhiko, Ayumi, and Haibara hear a dog barking loudly and a woman screaming. They head to the location of the sound, where they find housewife Yamada Sachiko and her beloved dog Pan being attacked by a man wearing a ski mask. Rather than rescuing his owner, Pan flees during the commotion. With help from Conan and the kids, Sachiko escapes danger. Sachiko, who doesn`t know why she was attacked, heads home with Pan once he returns, but Conan and the kids are curious about the masked man`s goals and decide to investigate.