After graduating from the police academy and being commissioned as an Inspector, Jiyong investigates the suspicious complainant Hwang Seong-gu and encounters a nationwide rental scam case. As Jiyong pursues the rental scam gang that evades proper legal judgment, he feels his vigilante rules being tested. And in the meantime, the four vigilantes involved receive threats from someone aware of their identities. They begin to sense the shadow of a great evil behind their adversaries.