When his father wasn't looking, his stepmother Kana and her son Yusuke had a physical relationship. Kana was tormented by guilt and a sense of immorality and tried to end the fruitless relationship, but Yusuke enjoyed the situation. Yusuke's young sexual desire knew no bounds and he became more and more uncontrollable with each passing day, until he began to desire Kana's body as soon as his father left the house...