Sumire, a single mother, has carefully raised her daughter Mao, a memento of her late husband. - One day, Mao brought a man with her. - Even though she thought he was a child until recently, Sumire couldn't hide her upset. - Mao says it's a "lover". - Sumire is confused and surprised. - The man with a fearless smile stole Mao's attention and suddenly attacked Sumire.