Mitsuhiko, Genta, Ayumi, and Haibara discover the body of serial blackmailer KUMO at a construction site. Conan is visiting the hot springs with Kogoro and learns about the case when Mitsuhiko contacts him. The Detective Boys witnessed a tall man fleeing the crime scene around the time the murder took place. The police believe KUMO was blackmailing ten men and one woman. However, all 11 of them have alibis, and the investigation comes to a standstill. When Conan hears about the situation, he notices a few inconsistencies...