Yuzuru ends up staying at his older brother's house in order to attend a prep school in Tokyo. Due to the stress of her entrance exams, she begins to be conscious of her brother's wife, who is kind and beautiful. A few days later, at dusk, Tsukasa returns home from shopping for his girlfriend, drenched in the rain. Yuzuru's wet hair, see-through bra, and adult sex appeal make her rational mind lose control, and she pours out her sexual desires on Gamushara.