A mystery drama revolving around a father who commits an unethical act in an attempt to save his daughter's life. Three years later, his actions return to haunt him, trapping him in an endless time loop.

Kim Joon Young is a famous surgeon, but he is not a good father to his daughter Eun Jung. One day he sees his daughter die in front of his eyes. From that moment the day repeats itself and he fights to find the secret of what happens together with the driver of the ambulance Lee Min Chul.