Tall, with a perfect figure and his qualifications as an Ivy League graduate, Kim Yi Han is Seoul's top male nanny. He is employed by Seo Do Young as a live-in nanny to look after her two young children, Eun Bi and Jung Min.

Choi Gi Chan is an University Botanic Professor with the "perfect genes." The drama is about an editor of a fashion magazine, Kim Dang Ja, who suddenly develops an urge to have her own baby despite opposing the idea of marriage. The story will talk about Dang Ja striving to look for a man with perfect genes to accomplish her mission. Gi Chan happens to be her "target" in order for her to accomplish her mission. The story later develops as Dang Ja must persuade him to do it without any commitments, which is a problem because Gi Chan doesn't believe in the idea of sex before marriage.

Marriage is thought to be the final conclusion of love: the most precious value in this world. But in reality, the marriage is not so sweet as recklessly imagined. Instead of being a sweet dream, the marriage in reality is a commitment and a promise to live among many kinds of obligation and sacrifice. It is rather the end of love than a sweet beginning. This is not what the lovers are aiming about. It's not marriage but living love they are shooting for. This is a drama of couple who has found a new way of living happily in Love.