She is ruthless, but she only works for her sister and best friend in the life of a big family, and her sister has lost the memory of her. She is elegant, but will make trouble unreasonably in front of her sister. She is indifferent, but she will show off her beauty for her sister and best friend. She is cowardly and simple, but she has won the trust of the three sisters. With the help of the three sisters, she has learned to defend herself. What kind of sparks of love will the four girls collide with the princes in the world of The Prince of Tennis? Will the two sisters think of their eldest sister? What kind of difficulties await them?