In 1950, shortly after North Korean forces, backed by the Soviet Union, seized most of South Korea, an American-led UN coalition swings into action to support the beleaguered South Koreans. General Douglas MacArthur, portrayed by Liam Neeson, the commander of the UN forces in Korea, formulates a daring plan aimed at striking behind enemy lines in the critical port city of Incheon.
At this juncture of the conflict, South Korea holds only a limited area to the south of the Nakdong River. This audacious strategy faces opposition from other military leaders, necessitating that MacArthur orchestrate a covert mission to secure vital intelligence from within the heavily fortified Incheon. This operation, dubbed "X-ray," involves meticulous work from Captain Jang Hak-Soo, played by Lee Jung-Jae, a former officer of the Korean People's Army who defected to South Korea after witnessing his father’s execution.
Alongside seven members of the X-Ray unit, Captain Jang disguises himself as part of a North Korean inspection team led by Park Nam-Chul, deftly infiltrating the command center in Incheon that operates under the aegis of the Soviet-trained commander Lim Gye-Jin. Lim, who is a protégé of Kim Il Sung, becomes increasingly wary of Jang's true intentions. The mission's principal goal revolves around determining the precise placement of North Korean defenses, which includes evading or neutralizing the dangers posed by mines and heavy artillery in the notoriously treacherous Incheon harbor.
Incheon is fraught with challenges, including a narrow access channel that could be easily obstructed by a sunken vessel. Consequently, if cut off from support, UN ships would face annihilation from stationed artillery. On the ground, Lim is suspicious of Jang's true "inspection mission," placing him under scrutiny while refusing to provide crucial maps of the mine locations, leaving the X-Ray team to navigate through communication with the Korea Liaison Office (KLO).
While executing the mission, Jang's focus shifts as he develops feelings for nurse Han Chae-Seon, played by Jin Se-Yeon. Tensions escalate as Lim identifies similarities between Jang and a known South Korean operative, creating further peril for the X-Ray group. As MacArthur mobilizes 75,000 troops and over 260 warships for the ambitious Operation Chromite, which faces impending threats from Hurricane Jean, the stakes are impossibly high.
In the midst of a hostile environment, with personal sacrifices and heroic escapes, the team must secure critical navigation charts revealing mine placements in the harbor to ensure a successful amphibious assault. The urgency of Jang's mission accelerates as he receives intel that time is running thin, forcing him to exercise steadfast determination and leadership.
Ultimately, the night of September 14, 1950, becomes pivotal. As MacArthur issues the command to capture the Incheon Lighthouse at midnight, Jang exhibits gallantry by navigating a tank, countering fierce North Korean resistance. In a climactic showdown, Jang signals the UN forces to commence their landing even as he pays the ultimate price for his valor. The ensuing chaos culminates in success, leading to the capture of Seoul and marking a significant yet tumultuous chapter in the Korean War, which claimed around 3 million lives before an armistice was brokered on July 27, 1953.
