Her remarried husband is busy and her stepson is a recluse... Yukari is happy but lonely, having been united with the man she loves. She witnesses her stepson Hiro masturbating. Unable to hide her excitement and agitation at his young, rock-hard dick, Yukari shuts herself in the bathroom and consoles herself by masturbating. When Yukari finds out that her stepson's recluse is because he's "hated by girls," she decides to teach him about the female body, step by step, in order to overcome his trauma about women. Yukari, who has not had sex with her husband, smiles at her stepson's awkward touching of her body, and eventually shows her feminine side as he leans forward and clings to her. Yukari is united with her stepson in a raw insertion, and Yukari feels irresistible when his young, hard dick swings its hips. Hiro, who is completely absorbed in the sex he just learned, seeks her out, and she regains her femininity. "Who feels better, my dad or me?" "Hiro's dick is the best!" Driven by a sense of guilt towards her husband, mother and son make love to each other's bodies day after day, crossing the barrier between parent and child in a forbidden act of incest...