Kang Bit-na, a judge who is possessed by a demon from Hell named Justitia, meets detective Han Da-on, who is more human than anyone else in a reality that is more hellish than hell. Justitia is sent by Bael to earth as a punishment for her wrong judgement and is tasked to kill 10 murderers who aren't remorseful in a year, along with her assistant, Valak. If she can't accomplish the punishment then she will die.

Kang Bit-Na (Park Shin-Hye) is an elite judge with a beautiful appearance, but she is actually a demon. Her mission as a demon is to kill evil people who lead other people to their deaths and don't reflect on their actions and are unforgiven for their actions. She sends these people to Hell afterwards. One day, Kang Bit-Na meets Han Da-On (Kim Jae-Young). He has a friendly and gentle personality. As a detective, his mind is sharp and he has a keen sense of observation. But, internally, he carries pain in his mind that nobody knows about. After Kang Bit-Na and Han Da-On meet with each other, their lives change greatly

The teaser after the end of each episode increase my interest to watch the next episode. This drama is good watch.