Classmates Rion and Hiroaki are unusually pure among modern couples, having only kissed so far. During the summer vacation, Rion secretly visited Hiroaki's relative's house. However, they had a depraved custom of 'sampling' all the women who were to become lovers or wives within their clan. Noticing Rion's cuteness and beautiful breasts, they seduced her in various situations. Her small breasts were thoroughly molested, and before she knew it, she developed masochistic tendencies, beginning to desire intercourse on her own...
