In 1950, just a few months after North Korean forces have overrun most of South Korea, an American-led UN coalition is deployed to Korea to aid the struggling South Koreans. General of the Army Douglas MacArthur devises a secret plan to attack behind enemy lines at the port city of Incheon. The risky strategy is opposed by leaders of the other military branches, forcing MacArthur to devise a clandestine operation to gather essential information from within occupied Incheon by coordinating a weeklong South Korean intelligence operation known as “X-Ray”.
The linchpin of this top-secret incursion, Captain Jang Hak-Soo of the South Korean navy Intelligence Unit (a former North Korean army officer who defected to South Korea after seeing his father executed in front of him by his fellow communist officers), and seven members of the X-Ray unit disguise themselves as a North Korean inspection unit and infiltrate the North Korean army command center in Incheon, coordinated by Soviet-trained Commander Lim Gye-Jin, a protégé of the North Korean leader, Kim Il-Sung. Their prime objective is to determine the placement of North Korean defenses (such as mines and artillery) and the tactical characteristics of the Incheon harbor (notorious for swift currents and major tidal surges), and secure a lighthouse crucial to the landing’s success.