After work falls apart, a woman returns home and begins helping at her grandfather's used bookstore. Bored by quiet country life, she discovers a new pleasure: playing naughty tricks on Mugi, an adult customer who often visits the run-down shop. A little teasing is enough to make him hard and bring him to ejaculation, creating a strange relationship between them. She claims she is merely relieving his urges, but the truth is that she only wants pleasure for herself.