All of the unscrupulous stepmother except for her husband are creampied.

Eri is her father's new wife. (...Why is this good woman like my father?) At one point, her son, Shinichi, has begun to be aware of Eri, who is too young and beautiful to call her stepmother, as the opposite sex. However, something happened that seemed to play with Shinichi's ulterior motives. Eri invited the man into his house and repeatedly cheated on him while his family was away. Shinichi accidentally witnessed the scene, and as he was anger erupted, his poor feelings glare in his mind... "I'll keep your father quiet," he says, and as he approaches her, Shinichi forces Eri into a forbidden physical relationship...