A father who lost his daughter in an accident repeats this "one day" over and over again, just to save his daughter. What secrets are waiting to be revealed in one day? The story of searching for the traces is all in the movie "One Day". Kim Myung-min plays the world-renowned chest surgery expert "Kim Jun-myeong". He will do his best to save a life, but he is a "zero-point dad". After witnessing the scene of his daughter's death in an accident, he fights to the death in the repetitive "one day" in order to recover the lost water. Byeon Yo-han plays the ambulance driver "Lee Min-cheol", Shin Hye-sun plays "Min-cheol's" wife "Mi-kyung", and Cho Eun-hyung plays "Kim Jun-myeong's" daughter "Eun-jeong".