Kim Ji-yong, a student at the police academy in South Korea, becomes the "Vigilante" at night and punishes criminals, who receive light sentences for heinous crimes. Ji-yong's actions catch the attention of Jo Heon, the head of an investigation team. Jo Heon initiates an operation to capture the Vigilante after learning about him through Choi Mi-ryeo, a news reporter, who covers the Vigilante's activities.