Misako faces the inevitability of abandoning her stepson, Kazuhico. She struggles with desire and jealousy as her little sister enjoys sex with the boy who has turned her life upside down. One last night won't be enough.
Kazuhiko becomes the center of the battle between Misako and Emiko.
The sister's youth makes Misako hesitate, and she faces the possibility
of having to leave her stepson, but her vagina demands something else,
and she's willing to do anything to keep Kasuhiko.
Emiko will try to rescue her sister from Kazuhito's clutches, allowing him to sexually degrade her, but she doesn't take into account that Misako does not agree with her sacrifice.
Kazuhiko takes advantage of the fact that his father won't be home that night, he has Misako all to himself, then an unexpected visitor arrives: Misako's exuberant younger sister.