While attending university, Yuuya lives as a boarder in his aunt's house. It's a temporary arrangement during his uncle's overseas business trip, but Yuuya is content with the daily life of being alone with his long-admired aunt. However, this routine steadily fuels his desire, and unable to hold back any longer, he secretly begins masturbating using his aunt's underwear as his fetish. One day, as he indulges in bliss while sniffing her panties, his aunt suddenly walks in on him... The atmosphere shifts instantly, and their relationship takes a bold, new turn.