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.

From Kim Won Seok, the writer of Descendants of the Sun, a drama about a special bodyguard with a background in special investigations and the Hallyu star he is supposed to protect.

On-yoo is an adult childhood cancer survivor. When he's not practicing with his boy band, Oh-yoo often volunteers at the hospital's pediatric cancer ward. One day, he recognizes the familiar face of an overdose patient.