Go Eun Nim (Lee Soo Kyung) lives with her biological dad, a stepmom, stepsister and a younger half-sister. Because of her dad’s problem at work, she has to sacrifice herself for her dad’s serious illness by accepting an offer to be a surrogate mother of a very wealthy chaebol family, Baek Sae Hun’s family (Ryu Jin). His infertile wife, Lee Seon Young (Go Eun Mi) made promise to keep a secret from the rest of the family because she couldn’t get pregnant after 6 years of marriage. Things get complicated when Eun Nim wants to keep the baby, and later on falls in love with Sae Hun’s younger brother, whom her stepsister has a big crush on, Baek Kang Ho (Jung Gyu Woon).