To fulfill the desires of clients seeking sexual relationships with relatives, Koki Takeki has unveiled the full details of his "Incest Project." An AV company employee who desires a sexual relationship with his brother's wife lures married women through a massage parlor. At this massage shop, women are successively seduced under the guise of receiving "body-slimming treatments" involving lewd procedures. Wearing blindfolds, they gasp in surprise as penises are inserted, yet quickly moan and climax, losing consciousness in ecstasy. Unaware that they are switching between brothers-in-law, they writhe in pleasure with different penises, reaching multiple orgasms. Three weeks later, the married woman returns, actively seducing the therapist, willingly accepting another penis, and climaxing repeatedly over several rounds.