Mantis, an ace assassin and a former colleague of Gil Boksoon, returns to a collapsed-order hired killer industry after his vacation. Upon reentering this anarchic world, Mantis encounters Jae-yi, his fellow trainee and rival, and Dok-go, a retired legendary killer, and realizes they are all vying for the top spot among the killers. A spin-off film of Kill Boksoon (2023).