When attempts to extradite notorious prisoners from the Philippines to South Korea are thwarted by a deadly attack at the airport, South Korean authorities commandeer the cargo ship Frontier Wolf for their next transfer. A cast of scoundrels boards the colossal vessel, including the callous heir to a criminal empire, escorted by two dozen seasoned detectives and under the watchful eye of a hot-headed Coast Guard captain. Despite the security, a plot to seize control of the ship simmers among the prisoners and soon erupts, but what neither the cops nor the criminals seem to realize is that they aren’t the cargo ship’s only cargo—and that they’re about to face a ruthless monster.