Summer, Showa 31. At the end of the season, Yuuko, living with her disabled husband due to an accident, moves in with her younger sister Mikiyo. Mikiyo's husband soon develops a strong attraction toward Yuuko. One night, drunk and overcome with desire, he forces himself on her. Yuuko resists fiercely, but her pent-up physical longing gradually takes hold of her emotions. The once-close bond between the two sisters begins to crumble as a result of this incident.