After admitting to the murder of 17 people, notorious serial killer Lee Woo Gyeom demands a chance to prove his extraordinary ability instead of facing the death penalty. A cure derived from his blood becomes a miracle drug capable of curing even terminal illnesses, and the world begins to see him as both a monster and its last hope. As Prosecutor Cha Ji Yeon, determined to secure a death sentence, tries to expose Woo Gyeom's ability as a fraud, Defense Attorney Park Han Jun fights to keep him alive in a desperate attempt to save his own terminally ill daughter. Meanwhile, although Woo Gyeom appears to be calmly awaiting judgment under the public eye, he is secretly preparing his revenge against a far greater evil. In the courtroom and the world beyond, where salvation and murder, justice and desire collide, will Woo Gyeom become a savior for all mankind, or merely another killer determined to complete his perfect revenge?