Kogoro, Conan, and Ran are invited to dog food company president Anna's birthday party and arrive at the yacht harbor. Shortly after the party begins, Anna is shot to death by a masked man wielding a shotgun. Inspector Megure questions vice president Inamura, director Machiko, and secretary Morishima, and Anna's ex-boyfriend Hyodo emerges as a suspect. However, Hyodo has an alibi: he was robbing Anna's apartment. Kogoro and the police suspect he fabricated his alibi, but...