The Sinaloa cartel, the largest drug syndicate turning the Americas into a haven for crime, gathers children by any means necessary to train them as hitmen known as sicarios. Surviving hellish training, Lee Se hwa rises into an elite assassin. However, a trap set by the boss forces him into the tragedy of killing his cherished comrade with his own hands. Betrayed, he destroys the organization and returns to Korea, the homeland that abandoned him as a child.

His peaceful life is short lived as criminal forces from home and abroad, lingering ghosts from his past, and relentless police task forces drag him back to the battlefield. Carrying a blade of vengeance in his heart, who is the true enemy Lee Se hwa must ultimately face?