Tak Dong-Kyung (Park Bo-Young) is an editor for a web novel company. Myul-Mang (Seo In-Guk), suddenly appears in her ordinary life. She makes a 100 day contract with Myul-Mang, risking her life and her love.
Myul-Mang is the existence of a middle manager between God and humans. He makes a contract with Tak Dong-Kyung.