Yui, a married woman living in an apartment complex, is frustrated by her husband, who never makes love to her for one reason or another. As she tries to ease her loneliness and dissatisfaction, her fingers gradually find their way to her nectar-filled private parts, where she passionately pleasures herself. Just as she reaches ecstasy, she feels someone looking at her, and when she turns to the window, there she sees the man next door, who has just moved in. The two, who were never meant to meet, end up in an affair so intense that they end up sweating after witnessing her masturbating...