After having the worst day of her life, Tak Dong-gyeong wishes for the world to end. A stranger shows up at her door to make that desire a reality.

Dong-gyeong realizes that the hundred-day pact with Myeol-mang comes with heavy consequences if she refuses to fulfill her end of the bargain.

As Dong-gyeong deals with a demanding new roommate, she looks for a loophole in her agreement with Myeol-mang to save her loved ones from doom.

Puzzled by Dong-gyeong's act of self-sacrifice, Myeol-mang decides to keep close tabs on her to figure out her true intentions.

In a desperate attempt to destroy Myeol-mang by winning him over, Dong-gyeong seeks the help of a romance expert.

Dong-gyeong looks for another subject to fall in love with. Na Ji-na attends a high school reunion hoping to see an old flame.

Myeol-mang comes to a difficult decision after being reminded of the part he played in bringing grief and sadness into Dong-gyeong's life.

After a short-lived reunion, Dong-gyeong has her love and trust in Myeol-mang tested while he navigates a world where she never existed.

Lee Hyeon-gyu shows up at Ji-na’s door to get something off his chest. Dong-gyeong goes on a shopping spree to prepare for a final goodbye.

Myeol-mang makes a heartfelt confession. A writer accuses Ji-na of plagiarism. Dong-gyeong makes a painful choice to save her loved ones.

After spending time with good company, Dong-gyeong returns to her old life while Myeol-mang finds himself transformed. Ji-na works on a new series.

Myeol-mang punishes criminals who run free. Dong-gyeong meets a ghost at the hospital. Ji-na and Hyeon-gyu feel a growing distance between them.

Myeol-mang keeps an eye on Dong-gyeong hoping to figure out who she is. Ji-na clears the air with Hyeon-gyu but makes up her mind to move on.

After promising a life together, Myeol-mang and Dong-gyeong make the most of the time they have left.

Upon receiving a second chance, Dong-gyeong moves forward with her life, while holding on tightly to the memories of her past.

Having found the person to spend the rest of her life with, Dong-gyeong finds hope and meaning for the future.