Yuusuke, who lost his mother at a young age, has an American stepmother because his father remarried. One day, his father goes out, leaving Yuusuke and his mother alone at home. Yuusuke was reading a book but gets excited seeing his glamorous mother cooking in the kitchen. As Yuusuke's sexual curiosity grows, he can no longer hold back and approaches his mother. Then, his mother takes his hand and gently begins to guide him into the world of sex.
