Conan and the Detective Boys run into Naeko Miike and Yumi Miyamoto, who were talking about Yumi's ex-boyfriend. Naeko Miike shortly receives a call from her acquaintance, Sakurako Yonehara, about a dead body. When the police arrive on the scene, the case seems to be a suicide, but Conan points out that the ripped-out suicide note does not match the ripped page of the victim's notebook. Also, the note is signed with the victim's full name, while all of her other notes were signed with only her first name. Thus, the case develops into a possible murder.