Akito and Ruriko have been married for five years. One day, when Ruriko was suffering from stiff shoulders, Akito brought her a flyer for a chiropractic clinic. On a day off, Ruriko went to the clinic with Akito, and for the first time, she felt pleasure when a man other than her husband touched her body. Oki, the chiropractor, noticed this change in Ruriko and played with her aching vagina during their second appointment. Despite feeling that they should stop seeing each other, Ruriko became addicted to Oki's penis. And Akito also began to feel something was off about the two of them...