Having married young, when frustration with their lives make Choi Ban-du and Ma Jin-joo regret their marriage of 18 years, a strange occurrence has them traveling back in time to the day before they met and into their younger selves.
38-year-old married couple, Choi Ban Do and Ma Jin Joo, were in love when they got married but now, hate each other and regret marrying at such a young age. Choi Ban Do has been burdened with being the breadwinner, and Ma Jin Joo is a housewife with low self-esteem. The couple travels through time and finds themselves as 20-year-old university students when they met for the first time.