Tetsuta and Aya are two siblings who lost their mother very early in their lives. Despite being loving and devoted, their father has since buried himself in work and hardly ever spends time with them. Tetsuta is fully accustomed to looking after his younger sister and cooking for the family, so he vehemently opposes his father's suggestion of bringing in a helper to tend to matters around the house and care for them. But his attitude changes the moment he meets this beautiful and kind-hearted housekeeper...