Jeon HyoSung is the oldest daughter of a rich family. Fifteen years ago, her family went on a trip and got involved in a car accident. Her parents were dead and when she woke up at the hospital, she lost her three-years-old sister, HyoMi. Since then, she has never stopped looking for her sister even though all HyoSung could remember about the little girl is the scar on her thigh.

Bang YongGuk is a professional gardener and works at many luxury houses. His mother adopted a little girl fifteen years ago and called her HyunAe. As HyunAe isn't his physical sister, he always has special feelings for her but keeps hiding that and turns it into a brother love in front of HyunAe. YongGuk doesn't want to let HyunAe know that she isn't his real sister.

Bang HyunAe, a normal highschool student, who looks boyish and little rough since she always stays around her big brother, YongGuk and her two close friends, DaeHyun and YoungJae. At night, she sometimes has a strange dream that she is staying in a glamorous house with a man, a woman and a girl who is older than her. But she doesn't really look like a boy, she still has long hair, thanks to YongGuk's bestfriend, JiEun, who always share the girly thoughts with her.

Kim HimChan, the only son of a big company's president, has set his eyes on HyoSung from the first time they met. But HyoSung still doesn't think of love yet. All of her mind is concentrating on looking for her sister HyoMi. HimChan used to be YongGuk's neighbor but then his family moved away and his father succeeded in bussiness so they became rich.