When Kogoro realizes that the death he's dealing with is not a suicide but a murder and that the perpetrator is one of his old friends, Conan tries to subtly give him hints to help him solve the case.

A famous lawyer calls for Kogoro at a fancy hotel asking him to follow his wife who may be having an affair. Kogoro, Ran and Conan then going to the man's house discover that the wife in question has been murdered? Who did it, and how was it done?