Korean emperor Lee Gon tries to close the doors to a parallel world which was opened by demons; a detective tries to protect the people and the one she loves.

A former taekwondo champion and an information desk worker aspire to chase their dreams in a world that isn't kind to those with mediocre credentials.

Hwang Shi Mok underwent brain surgery as a child to curb his violent temper, which left him devoid of emotions. Hwang becomes a prosecutor known for his piercing intelligence and logic, but he is ostracized because he lacks empathy and social skills. He is also one of only a handful of upright prosecutors who have refused to take bribes. One day, he encounters a stabbing victim while investigating corruption. He meets Lieutenant Han Yeo Jin at the crime scene. They join forces to root out corruption at the prosecutors’ office and solve a serial murder case.