When serious criminals evade punishment by the law, a survey message reaches all citizens over the age of 18 asking whether that criminal should receive the death penalty. If more than 50% of the voters choose for the individual to receive the death penalty, they are killed by an anonymous virtual persona known as "Dog Mask". Meanwhile, the police are also in pursuit of "Dog Mask", and three individuals become involved in this chase. Kim Moo Chan is the leader of the first investigation team at the Southern Regional Police Department. Kwon Seok Joo is a famous former law scholar who killed the rapist who attacked his daughter and then turned himself in to the police. Joo Hyun is a police officer who worked for five years in the Cyber Security Bureau of the Seoul Central Police Department.
