\Once you're in, the only way out is death!\ Former hitman Jeong Do-gyun thought he'd left that life behind. Now retired, he keeps a low profile, working at a café run by Gu Sang-hyeok—the closest thing to family he has following their days spent in an orphanage. But one day, Sang-hyeok vanishes without a trace. Following his trail, Do-gyun finds himself on a remote, mysterious island—only to discover a horrifying truth. The island is a prison, filled with kidnapped victims forced into slavery, watched over by merciless killers. And to make matters worse, the man who murdered his family is here, too. With a vengeance burning in his veins, Do-gyun prepares for the fight of his life. It's him against an army of ruthless assassins—only one side is making it out alive.