Aya becomes depressed when she finds out that her other sisters have already made a move on her beloved elder-brother before she gets a chance to. Will she be able to win him over instead?

Keiichi is a young man that lives with his two younger sisters, Ririna and Momoka. While their parents are out of town for the entire summer vacation, Keiichi discovers Ririna’s vibrator in the bathroom. She agrees to do anything he wants in exchange for keeping quiet about it.