Lee John Doe

Father: Lee Sang-woo
you: Ha Sung Jung
Boss/Partner: Kim Sung Min
Friends: Ahn Jung Ho (wet)
Kim Min Wook
Worm

Lee Jung Do is a martial artist, holding black belts in several disciplines. He worked as a delivery boy at his family's cafe and enjoyed hanging out with friends without making any long-term plans. One day, witnessing an attack on a police officer, Lee Jung Do immediately intervened and subdued the attacker.

It turns out the officer he rescued supervised parolees. While the officer recovers from his injuries, Lee Jong Do receives an unexpected offer to take his place. Initially, the job seems simple: enforce rules and prevent violations. However, it soon becomes clear that reality is far more complex and dangerous than initially expected.