Flu

A tense outbreak thriller unfolds in Seoul as two smugglers, Ju Byung-woo and Ju Byung-ki, stumble upon a grim loss at sea when a shipping container carries illegal immigrants who die from an unknown illness. They seize the lone survivor, Monssai, and film the bodies to show their boss in Bundang, but Byung-woo falls ill and Monssai manages to escape. In a rush, the brothers rush to a clinic, and the contagion spreads as the virus moves through the staff and other patients, signaling the beginning of a citywide crisis.

At the Contagion Center in Bundang, Dr. Kim In-hae faces authority after losing crucial data when her car tumbled into a mine shaft the day before. Her bag is recovered by emergency response team members Oh Ji-goo and Bae Kyung-ub, and Ji-goo hands the bag to In-hae’s daughter Mi-reu after answering a call. As Byung-woo’s condition deteriorates, he begins vomiting blood, forcing his brother to rush him to the emergency room where the pair confront an unknown flu together. Byung-woo dies, and Byung-ki’s desperate pursuit of his brother puts hospital staff in harm’s way as he resists questions about the container.

The following day, an expanding wave of symptoms prompts a coordinated response with the KCDC. The hospital staff incinerate the shipping container, hoping to halt the source, but the disease has already spread: rats that fed on the contaminated remains escape into the city, spreading the mutated virus. The medical team determines the culprit to be a highly aggressive variant of H5N1 that can kill within 36 hours, triggering a formal quarantine of the city.

Monssai finds a chance to intervene when he saves Mi-reu from being struck by a car, all the while aware that his presence could accelerate transmission. Mi-reu reaches out to Ji-goo for help tracking the sick man, but their search yields little. Rumors swirl, panic spreads, and Ji-goo’s efforts to protect others intensify as he saves a woman from an escalator, only to lose sight of Mi-reu in the crowd.

In Bundang, officials are slow to acknowledge the need for quarantine, and the situation rapidly deteriorates as people collapse in the streets. The healthcare system and communications networks strain under the load, and the quarantine is officially implemented. Politicians and administrators pull back to Seoul to brief the Prime Minister, whose public address inflames fear rather than soothe it.

In-hae stays behind in Bundang and teams up with Ji-goo to find Mi-reu. They eventually locate her in a looted supermarket where symptoms are visible and riot police struggle to restore order. The trio fights their way to a path toward Seoul, but Mi-reu’s symptoms threaten their escape when passage is denied. They finally glimpse a way out, only to see Mi-reu’s condition worsen and the window for departure close.

That night, a heavy quarantine is reinforced by the military, allied forces, and health authorities. The population is moved to a camp outside the Tancheon Sports Complex, while those showing symptoms are confined to an infected quarantine zone beneath the stadium to receive care. In-hae hatches a plan to shield Mi-reu, slipping her through examinations and keeping her mask in place to prevent further contagion. In the IQZ, Monssai is discovered, and a proposed direct antibody transfusion for a patient is rejected, which pushes In-hae to take a more personal route by secretly beginning a transfusion for Mi-reu. Her attempts become more urgent as Mi-reu’s condition worsens and she is ultimately moved to the IQZ for treatment.

Conditions inside the camp breed unease: communications are cut, living standards deteriorate, guards in gas masks patrol, gunfire is used to deter birds from spreading the disease, and rumors circulate that the infected are being killed. Pressure from WHO representative Leo Snyder and political leaders forces the president to abandon a pledge to release the uninfected after 48 hours, sparking clashes. When an infected soldier is shot dead, the mob erupts, and Ji-goo is seen rescuing Mi-reu from a pile of burning bodies that are being destroyed as a precaution.

As In-hae and the medical team flee the chaos, Byung-ki executes a suicidal attack to avenge his brother, killing Monssai in the process. Mi-reu begins to recover, and Ji-goo escorts her toward the highway to reunite with In-hae. But Gook-hwan, an infected agitator, leads the mob toward the highway and opens fire, triggering a fierce exchange between the rebels and the soldiers.

Ji-goo hides Mi-reu, who nonetheless makes a full recovery. Gook-hwan’s desperate bid to transfuse Mi-reu’s blood is thwarted when Kyung-ub intervenes, and the insurgent is killed in the scuffle. As Mi-reu escapes to the front of the mob, the confrontation on the highway intensifies. In-hae is wounded while attempting to prevent Mi-reu from crossing the containment line, but Mi-reu shields her mother, and the crowd answers her plea with protective solidarity. The president orders the soldiers to stand down, and Snyder is forced to cancel an air strike. In a hopeful turn, Mi-reu is sent to Seoul to help in vaccine development while medical teams are mobilized to Bundang, signaling a fragile step toward containment after a harrowing outbreak.

Last updated: October 09, 2025 at 16:19

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