After losing his father and falling into loneliness, Ataru quit his job and began living off his father's insurance money. Into his life suddenly returns his mother, Hitomi, who had run away from home. Ataru cannot accept her return wholeheartedly and constantly acts out in defiance. Yet deep inside, he has never stopped thinking about her. Despite his conflicted emotions, life with his mother becomes a new beginning for him. But one day, his mother reveals the true reason she had run away...