Choi Ban Do and Ma Jin Joo are both 38-years-old and a married couple. Choi Ban Do has been burdened with being the breadwinner and Ma Jin Joo is a housewife with low self-esteem. Even though they loved each other when they married, they now hate each other. They both regret marrying at such a young age. The couple travel through time and find themselves as 20-year-old university students, when they met for the first time.