Ren Ichinose stars in this GOS production from the Documentary: Consanguineous Incest series. Takeda Takefumi devises an affair plan centered on incest, fulfilling a client's desire. The story follows an older brother who has secretly harbored lustful feelings for his younger sister, whom he raised as a parent. Under the pretense of taking her to a hot spring inn to celebrate his wedding, he lures her into the trap. At the inn, the brother pretends to pass out drunk, allowing a stranger to seduce the unsuspecting sister. Hidden cameras capture her as she writhes and moans, torn between guilt and pleasure, whispering "We'll get caught" as she gives in. She climaxes repeatedly as the man thrusts into her. Afterward, blindfolded and unaware, she is penetrated again—this time by her own brother taking the man's place. The camera records her pleasured reactions as she unknowingly commits incest, taking her brother's cock from behind.