Shinji Nogami has discovered he has a cuckold fetish. It began when he accidentally saw his wife's panties while she was asleep on the couch, during a night he let a subordinate stay at their home. Since then, a deep darkness has grown within him, and he's developed an urge to expose his wife to other men. One day, he learns of a place known as "The Mansion of Cuckolding"—an encounter that will drastically change his life.