This series is about a 19 year old girl, Yoo Min who was being abandoned after the death of her mother. She lives alone with her adopted brother, Kang-Pyo. She accidentally meets Seung-Jae, the younger brother of Min-Jae. By chance, Yoo Min actually had a crush with Min-Jae, a doctor who treats her brother illness for a long time. To fight off his mother demand, Min Jae gets in an engagement contract with Yoo Min and they all end up living at Min-Jae's house. Unexpectedly, Yoo Min and Seung-Jae are going to the same high school. From there, Seung-Jae secretly loves Yoo Min. On the other hand, Yoo Min's father who got amnesia from a car accident is looking for her again after 15 years old she had been abandoned by her neighbors. The conflict comes when the people who living in Min Jae's house are actually related to Yoo Min's abandonment. They are the neighbours who stole the inheritance and abandoned her when she was four year old.