Ryo has enjoyed five modest but happy years of marriage to her husband Tetsugaku, who works in sales at the same company. One day, while he is away, his boss Saji visits and claims Tetsugaku made a costly mistake at work. Saji pressures the confused wife into a slave contract. Ryo offers her body to protect her husband, but the anal training that follows brings her pleasure and humiliation unlike anything she has known. Her reason slowly erodes as she repeatedly spreads her ass and climaxes for him...