In the Joseon era, the court is steeped in tension as nationalists view King Lee Jo as a puppet of the Qing dynasty. His son, the Crown Prince Yi-yeong, Ju-hyuk Kim hatches a daring plan to purchase European arquebuses in a bid to push back the Qing, confident that new firepower could tilt the balance of power. But war Minister Kim Ja-joon, a formidable influencer at court, uncovers the scheme and twists it into a much darker narrative of rebellion. He secretly meets the Europeans and discovers a grim secret: a crewman locked away in a cell is slowly turning into a demon, a precursor to the nightmare looming over the capital.
Lee Young pleads with the aging king to take a stand against the Qing now that firearms exist, arguing that modern weapons could change the fate of their nation. The king, however, remains stubborn and deaf to the prince’s pleas, clinging to a fragile status quo. In a desperate act of penance that he hopes will spare his subordinates, Yi-yeong then sacrifices himself. The shockwave from his death ripples through the court and the region, while Joseon forces move to strike at the European ship and seize the arquebuses. Yet the victory is hollow: a Joseon soldier is bitten by a zombie, a contagion that crawls from the ship to a village, setting off a chain of infection that threatens to swallow the realm.
The undead are a chilling presence: they crave meat and blood, are drawn to the noise of life, but are repelled by sunlight. They can be killed definitively by decapitation, piercing the heart, or severing the spinal vertebrae, though other methods often fail to stop the spread. The outbreak forces a grim test of leadership and loyalty as Lee Young’s last wishes come into sharper focus. He had arranged for his wife, Gyeong-bin, and their unborn child to be raised by his younger brother in China for safety, a plan that will soon collide with a military and political maelstrom.
Lee Chung, the younger brother who grew up abroad within the Qing, returns with Hak-Su, landing in Jemulpo. He faces a brutal reception: assassins loyal to Minister Kim and other ministers plot a coup, and their commotion draws a horde of zombie villagers. The Jemulpo partisans rally behind Lee Chung—led by his former lieutenant Park Eul-ryoung—and an archer named Deok-hee, whose courage burns brightly in the chaos. The group pleads for Lee Chung to take a throne that isn’t his by birth, but he declines, seeking a chance to rebuild rather than seize power. Deok-hee becomes a pivotal ally, a fearless presence in the fray.
The crisis intensifies when the last surviving assassin is captured by Kim, who himself is infected. The ministers, craving power, allow a concubine he has infected to pass the contagion to the king, triggering a full-blown zombie uprising inside the court. Lee Chung arrives at the royal court, requesting an army to crush the undead scourge. The paranoid king, swayed by ministers, agrees only if Lee Chung vows not to pursue the throne—an order that the ministers soon twist into denial of the outbreak, framing it as a mere civil rebellion. As a result, Jemulpo’s partisans are arrested, and Lee Chung and Gyeong-bin are forced to attend a banquet for a Qing delegation.
At the banquet, the king fully becomes a zombie. Kim kills the monarch, unleashing the undead in a bid to eradicate opposition and undermine the Qing presence. But Kim’s own hunger for power proves fatal: bitten by a zombie and cornered by other ministers, he slays them all, cuts off his own hand to slow the infection, and proclaims himself king in a frenzy of paranoia and ambition. The palace erupts into chaos, and Gyeong-bin urges Lee Chung to act not out of fear but to protect the people. The Jemulpo faction, freed from prison, joins the effort to keep the undead from spilling into the capital.
A plan forms to draw the zombies into a massive, fiery trap inside the palace. The effort is crippled when Hak-Su and an infected Park are killed by Kim, thwarting the explosion’s timing. Undeterred, Lee Chung presses on, battling wave after wave of undead and contending with Kim in a brutal clash that moves through the burning halls. Deok-hee fires a flaming arrow into the palace, and Lee Chung uses the blaze to ignite a pool of oil, transforming the siege into an inferno that consumes the royal residence.
Rising to the roof, Lee Chung confronts Kim in a decisive duel. The fight ends with Lee Chung prevailing, and soon the sound of reinforcements—soldiers and commoners—floods the palace, wiping out the remaining zombies and breaking the threat against the capital. In the wake of the catastrophe, Lee Chung recognizes a deeper, enduring truth: the resilience of the people gives Joseon a future worth fighting for. Rather than flee to China, he chooses to stay and lead his people as the new king, guiding them to reclaim their city and secure the port where the nightmare began, ensuring that the nation survives the night of the living dead and steps toward a fragile, hopeful dawn.
