To fulfill a desire for incest, Taki Takefumi devises a plan. The client is a younger brother harboring feelings of inferiority toward his older brother, longing to have sex with his sister-in-law. Using footage of the sister-in-law masturbating, secretly recorded by the younger brother, a private investigation agency-styled crew makes contact with the target. Threatened with exposure, she is coerced into surrendering her body in exchange for keeping the video hidden, and is lured to a hotel. As the man manipulates her body, she reacts sensitively, her genitals becoming wet. Bound tightly and tormented with sex toys, she is brought to orgasm after orgasm, begging for cunnilingus she never receives from her husband. Climbing atop the man once more, she rides him vigorously, moaning loudly in ecstasy. Even when the younger brother joins, she continues writhing her hips without knowing his identity due to being blindfolded, wracked with pleasure. Even after the blindfold is removed, the threesome continues until she is finally driven to ultimate climax.