A special project tackling the taboo theme of incest. Directed by Koichi Takahashi, this bold hidden camera production fulfills a client's request by secretly filming intimate acts—from close contact and fondling to full penetration. The son, who discovered his mother's affair with his grandfather during middle school and developed forbidden desires, becomes the client. His mother, an art student, secures a joint exhibition with a professor, and at her son's urging, agrees to pose as a model. Though hesitant about nude modeling, she agrees to help her son, but her arousal is quickly noticed by director Takahashi, who poses as the professor. He takes her to a hotel and makes love to her. Continuing under the guise of modeling, mother and son engage in intimate contact—naked, touching, and caressing each other. As she pants and shows clear signs of pleasure, the director penetrates her in front of her son, driving her to ecstasy. Then, quietly, the son takes the director's place. Overcome with excitement, he accidentally reveals himself while his mother moans in pleasure, unaware of the switch. After persuasion, the mother reluctantly agrees to incest—just once—and screams in climax as she succumbs to overwhelming pleasure.