Mouri, Ran, and Conan are attending a play when Conan overhears one of the actor's murder plan. He is later found eaves dropping and placed in a coffin. Later he over hears the other two actors who also plan a murder, meaning a murder triangle has been formed. After they seemingly all die, Conan is revealed to manage to save all of them having escaped from the coffin through a back door.

Ran decides to phone her father to ask for help, but he is busy playing Mahjong. Later Eri realizes that a tape recording was used to create the alibi of her husband. The wife then reveals that her husband cheated on her with a friend's wife, but Eri revealed he did so because he was jealous that his wife was inlove with the husband of the women he was cheating on. Later, Conan finds out Mouri indirectly helped his wife solve the case.