A home tutor, Min Yoongi works definitely fine until he met his first girl student, Yoo Hyesoo. She confessed to him on the last day of their class but he rejected her. Three years later, they met again but now he is working as a young doctor in the same university as Hyesoo. Since Yoongi was Hyesoo's first love, she fell in love with him again. But, will he accept her or reject her for the second time? What was the reason behind his rejection before?