Lee Kang Joo is a single mother who was abandoned by her previous boyfriend, Yoo Ho Nam. Ho Nam did not know that Kang Joo was pregnant with his child and went abroad to study. When Ho Nam returns to Korea, Kang Joo tries to cover up the fact that Byul is their daughter. Choi Seung Hun is the son of Jung Soo Hee who is Kang Joo's mentor and boss. He has been pursuing Kang Joo since he was in high school but she has always been unresponsive to his advances. Will he finally convince her that his love for her is real? How will he respond to finding out that she has a daughter and who her father is?