Young-woo is on the verge of leaving his company after completing his final mission to eliminate a drug dealer. Just as he is about to board a smuggling ship to China, he hears the news of his mother's death, who he lost contact with 20 years ago. There, he discovers he has a half-sister with the same name, Young-woo! Meanwhile, the organization, realizing Young-woo is still alive, tries to eliminate him and find his sister...