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.