Nana dislikes her stepfather. Despite her complicated feelings, she decided to support their remarriage for the sake of their livelihood... However, her stepfather's true intention was Nana's slender body, the reason behind his decision to remarry her mother. Today, while her mother is away, the stepfather continues his "sex education" on Nana, who, being timid, can't refuse and gradually transforms into the type of woman her stepfather desires...