Based on the erotic game by Blue Gale.

The latest series of the Airi storyline finds the three main characters adjusting to their current setting of an open adult relationship. The setting is completely disturbed when Airi and Marina's mother, Kayako (華代子), returns and seeks to "rebuild" her relationship with the stepfather, unaware of him having sexual relations with her two daughters. Also the stepfather is becoming more and more abusive to Airi who has been challenging their relationship with another young lady.