To fulfill a desire for incest, Kuriki Takeshi devises a plan to secretly record a mother engaging in sexual acts with her son. After receiving a plea from a mother who was caught by her husband's father, Kuriki steps in between the father-in-law and the married woman, attempting to resolve the conflict with a single sexual encounter. However, the aroused father-in-law aggressively pushes forward, forcing Kuriki to proceed by filming evidence. The married woman insists she isn't enjoying it, yet gasps heavily when her genitals are licked. When the father-in-law fails to maintain an erection, Kuriki proposes satisfying the woman using his own penis, gaining consent before penetration. Simultaneously, she sucks the father-in-law's penis to make it erect, then switches positions, straddling him in cowgirl position while verbally confirming the hardness of his cock. The scene captures her losing control completely as she is thrust into by two penises.