Ryo has been married to her husband, Tetsugaku, who works in sales at the same company, for five years. Ryo lives a modest but happy life. One day, while Tetsugaku is away at work, Tetsugaku's boss, Saji, visits and tells her that Tetsugaku has caused a great deal of damage to the company due to a mistake he made at work! Confused, Ryo is approached by Saji, who proposes a slave contract. Ryo offers her body for her husband, but from that day on, her anal sexual development begins...