With their mothers away on a trip, the guys are left behind and stay over at their cousin Natsuki Hoshino's place for meals and care. Natsuki has always had a strong interest in sex, and every time they stay over, she tempts them, relentlessly jerking them off. Once again, she comes on strong, rubbing her big tits against them to seduce. Unable to resist her charm, the guys give in to her advances. Beneath Natsuki's kindness and attentiveness lies a hidden desire, and their relationship heats up intensely once more.