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.

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