When torrential rain stops the trains after overtime, busty office worker Umika Minamisawa invites her married boss to stay at her nearby home. They arrive drenched, her soaked white shirt turned transparent, and she seems to enjoy his stare. He resists until she changes into loose loungewear that exposes deep cleavage and the edges of her plump pink areolas. His restraint snaps and he buries his face in her breasts. She responds by revealing the sensual side she normally hides, surrendering both body and heart. With their voices swallowed by the rain, the married boss and his employee keep having sex until morning, sharing a secret neither can ever reveal.