Kippei Katakura is a good-looking boy who likes to be a player. He likes to change girlfriend everyday and he doesn't care much about the teacher who keeps yelling at him because he kisses the girls at school. One day while he is planning to met one of his fans, his sister calls him ordering to go home quickly. The moment he opens the door of his house, he is unexpectedly confronted by a little girl who is staring at him with her sweet eyes. He later finds out that the little girl's name is Yuzuyu and she is five years old. She is his cousin, and since her mother abandoned her, Kippei now has the new responsibility, which is imposed by fellow family members, to take care of her. He has to bring her to school and pick her up when she is ready to go home, he has to cook her what she likes and what she used to eat when she was with her mother, most of all he has to behave like a brother. Yuzuyu is a sweet girl and soon he discovers how much he cares for her. Even at school his playboy behaviour changed, because he realized his love for his classmate, Kokoro who also likes him, but she keeps on wanting to stay away from him. How is Kippei’s life is going to change? Will Yuzuyu be able to met her mother? Let's find out.