After a fierce argument with his wife, Minako leaves home, leaving Tatsuya desperate for reconciliation but unable to initiate a proper discussion, burdened by inner turmoil. At this time, his sister-in-law Kana, concerned for him, offers to mediate. Hoping for help, Tatsuya invites Kana to his home, but she gradually closes the emotional and physical gap between them, unintentionally stirring his emotions. Trying to escape the tension, Tatsuya retreats to the bath, but Kana follows, inviting herself in. In this charged situation, he loses control of himself completely.