Akira happens to come across his neighbor washing her car and discovers she's not wearing any underwear. Captivated by the sight, he becomes naturally aroused and ends up receiving sexual favors from the aunt as thanks for helping with the car wash. Initially thinking it was a joke, she becomes flustered by Akira's serious demeanor and gradually gives in completely. Even after he leaves, the aunt remains aroused, passionately having sex with her husband that night. The story unfolds as their intimate relationship deepens.