Shinichi encounters Heiji, a high school detective from Osaka, who is chasing a purse snatcher. With Shinichi's help, Heiji catches the snatcher, but they hear the sound of breaking glass and a woman's scream from the house of composer Kazuo. When Shinichi and his friends rush to the scene, they find Kazuo in a daze and his assistant, who has been fatally injured by glass shards.