Pandora

Jae-hyeok works at the aging Hanbyul Nuclear Power Plant, the town's main employer. He lost his father and brother to the plant in earlier years and now lives with his mother, sister-in-law, and nephew Min-jae. He dreams of leaving the town to join a fishing vessel, but is discouraged by his friends and especially his fiancée Yeon-joo.

Pyeong-seok, a lead operator, joins a coalition of workers and anti-nuclear activists pressing the president to shut down the plant due to safety concerns. They argue the aging systems risk a major disaster, but their pleas are dismissed by the senior operators and the Prime Minister. This tension foreshadows the crisis to come.

An earthquake jolts the town, triggering an overheating reactor as the plant's aging safety protocols fail under stress. Engineers scramble to cool the core, but their attempts are hampered by the plant's deteriorating infrastructure. The imminent danger becomes painfully real for everyone nearby.

Hang's administration debates whether to vent radioactive steam or evacuate nearby populations to relieve pressure. Lacking a solid contingency plan, officials decide to evacuate residents closest to the reactor, but the only exit route soon becomes gridlocked. The town faces a slow, failed exodus as time runs out.

The attempted cooling fails and the reactor building explodes before the pressure release valves can be opened. The blast destroys parts of the facility and injures or kills many plant workers who were attempting to escape the danger. Jae-hyeok rescues his friend Gil-seop and several others before collapsing from radiation poisoning.

The KCDC quarantines residents near the reactor, while Yeon-joo uncovers evidence of the explosion and broadcasts it. Evacuees are locked inside the evacuation center as authorities withdraw, leaving Mi-sook the junior nurse to tend the ill. Tension rises as fear and confusion spread through the town.

Yeon-joo and the town residents manage to break out of the evacuation center and hijack a bus to bring their community away from the danger. The improvised evacuation becomes a fragile lifeline for many survivors. The town bands together to flee the toxic area.

Firefighters work to cool the reactors but some suffer radiation poisoning themselves. Hang, gripped by guilt and despair, orders them to use seawater in an attempt to decommission the reactors entirely. The mounting crisis reveals the limits of authority and resources.

Scientists discover a growing crack beneath the storage tank holding spent fuel, raising the risk of a catastrophic meltdown. Army engineers refuse to step in, and Hang appeals to the plant workers to seal the cracks as a last resort. Time is running out as radiation leaks worsen.

At first, Jae-hyeok refuses the dangerous mission, but Gil-seop's insistence and the need to save lives persuade him to join. He reaffirms his commitment to his colleagues and the town, even as his own health deteriorates from radiation. He calls Yeon-joo to say goodbye before heading back toward the town.

The team must seal the door to the waste room and blow up the tank at the same time, a move that guarantees the fuel rods plunge into the basement. Jae-hyeok is the only one who can operate the explosives, and his worsening illness makes the choice a deadly sacrifice. He broadcasts a farewell message to his family and Yeon-joo via his helmet camera.

Jae-hyeok sacrifices himself to trigger the containment sequence, sending the fuel rods into the flooded basement and preventing a wider nuclear disaster. The blast allows the remaining workers to seal off the area and evacuate, saving many lives in the process. The town begins to recover, honoring the sacrifice.