An Alzheimer’s stricken detective Choi Jang Soo (Yoo Oh Sung) decides to do his best to make his family happy after he learns that he has little time left to live. Oh So Young (Chae Si Ra) and Choi Jang Soo, depict a true-to-life story of a married couple. The couple goes through a challenging time when fund manager Huh Jun Ho (Jo Yeon Woo), who has loved So Young for a long time, and ex-criminal Jo Hyun Soo (Choi Yeo Jin), who loves Jang Soo, appear in their lives. The drama depicts the everyday reality of fathers who have no other choice but to neglect their families to earn the living and mothers who turn into stouthearted “warriors” who can do anything for the sake of their families.