Once rivals in school, two brilliant doctors reunite by chance — each facing life's worst slump and unexpectedly finding solace in each other.

When Ji-won, a 37-year-old cancer patient, walks in on her husband and best friend, she realizes her whole life has been a lie. What’s worse, she dies a tragic death at the hands of her husband. Would things have been different if she had made different choices? Fortunately for Ji-won, she is given the chance to rewrite her fate when she is reincarnated as her younger self. This time, she vows to live a happy life. But first comes revenge. Her plan? To marry off her now former best friend to her lying, cheating husband.