In a quiet restaurant in America, Gon (portrayed by Jang Dong-gun) quietly studies a lone little girl at her table, setting a grim tone from the start. He heads to the warehouse behind the eatery, where Ha Yoon-guk (portrayed by Park Byung-eun) is sealing a deal with a group of Russian thugs. Gon moves with cold precision, eliminates the group, and retrieves Yun-guk’s laptop. When a sound comes from behind the door, he shoots through it—only to realize the little girl had followed him. The child’s death is a brutal moment that leaves Gon deeply traumatized, driving him to drink as a way to forget the horror of the encounter.
Gon’s close circle includes Alvaro (portrayed by Alexander Wraith) and Juan (portrayed by Anthony Dilio), his two Colombian teammates. They bring Gon back to their boss, a Chinese-American Triad named Dai-Ban (portrayed by Dana Lee). A rift surfaces quickly: Alvaro’s punch in response to a previous provocation stirs a vendetta, and Gon’s warning to Dai-Ban—never again send men to his home—rings with new weight. The mission then shifts to Seoul, where Gon must tie up the loose end by finding Mo-gyeong, the little girl’s mother, who works as a risk manager at a firm. The assignment immediately forces Gon to reckon with the girl’s tragic fate as he quietly studies Mo-gyeong’s routine and routine hospital visits to her ailing mother.
Mo-gyeong’s life becomes entangled with law enforcement and corruption. Detective Park from the financial crimes task force explains that Mo-gyeong’s supervisor, John Lee (portrayed by Jun Kim), may have ties to organized crime. Yun-guk had gained access to John Lee’s accounts to launder money and had begun selling that leverage to the Russian mob. Park asks Mo-gyeong whether her husband left any evidence that could implicate John Lee. The mounting stress pushes Mo-gyeong toward a hospital, where she and her daughter’s memory torment her. Into this precarious equilibrium steps Asing (portrayed by Rich Ting), a Chinese-American street assassin sent by Dai-Ban to eliminate Mo-gyeong after he finishes off the other loose ends. Gon arrives just in time to defend her, engaging Asing in a brutal clash. Asing escapes briefly but returns to press the threat in a parking lot; Gon intervenes, killing him, but the danger to Mo-gyeong remains.
Dai-Ban sends Chaoz, Juan, and Alvaro to Seoul to locate Gon. Chaoz strikes first with a swift, brutal kill of a black-market arms dealer and his bodyguard, clearing the path to Mo-gyeong’s apartment for the approaching threat. Inside the apartment, Mo-gyeong discovers a pen-drive containing the crucial file, but Park’s subordinate betrays Park, shoots him, and hands the drive to John Lee. Byun’s thugs then move in to kill Mo-gyeong, but Gon intervenes by calling to warn her and stepping into the line of fire. He fights off several attackers while Chaoz and the others arrive, finishing the remaining threats. Gon creates a distraction to protect Mo-gyeong, knocking Alvaro off balance and starting a fierce firefight with Chaoz and Juan. While Mo-gyeong escapes, Gon fights to uncover the truth—promising to reveal what happened to her daughter.
The battle lines momentarily shift as Juan and Alvaro press their advantage, but Gon outmaneuvers them and holds them off. In a cruel twist of fate, Juan shoots Alvaro, and Gon uses an improvised explosive made from a microwave to eliminate Juan. Meanwhile, Mo-gyeong fights to stop the money transfer to John Lee’s account, and Byun stabs John to death, exhausted by Lee’s abuse of power. The city crackles with danger as Gon and Chaoz exchange blows, both badly wounded. Despite the mounting odds, Gon spares Chaoz at a crucial moment, unwilling to kill his close ally.
The tension crescendos when Byun locates Mo-gyeong and tries to brutalize her; she defends herself, stabbing him to death. After a tense conversation with Chaoz, Gon urges Mo-gyeong to act decisively and shoot the next person who enters from the lift because he believes that person may be the killer of her daughter. Gon himself returns and is shot by Mo-gyeong. Chaoz arrives soon after and seizes the shotgun from Mo-gyeong, poised to end the situation, but a dying Gon asks him not to. Chaoz steadies Gon’s hand as he dies, and Mo-gyeong, realizing Gon’s actions may have indirectly killed her daughter, reaches out via radio in an attempt to connect with him. A final flashback reveals Gon’s mother—who abandoned him in the United States and later killed herself—speaking to him with a quiet hope that they could have a better life if they moved to America, a memory that fuels his quiet weeping in the end.
