Rampant

In the Joseon dynasty, its king Lee Jo is viewed as overly deferential to the nearby Qing dynasty of China. His son, crown prince Lee Young, engages in a plot to buy European arquebuses to drive away the Qing. The plot is exposed by Minister of War, Kim Ja-joon, who holds influence over the king and frames it as a rebellion. Kim meets the Europeans and learns that they have brought zombies (called 'night demons'). The crown prince commits suicide as penance so that his subordinates will be spared. Joseon forces destroy the European ship and retrieve the arquebuses, but a Joseon soldier is bitten by a zombie. The soldier returns to his village, where he turns and spreads the infection. The zombies crave human meat and blood, are attracted by sounds, repelled by sunlight, and are stopped by decapitation or piercing of the heart. The crown prince left a request for his wife Gyeong-bin and unborn child to be brought by his younger brother Lee Chung to China for their safety. Lee Chung had previously been left out of Joseon's order of succession and grew up abroad in the prosperous Qing. Lee Chung returns with his companion Hak-Su, landing in Jemulpo, but is attacked by Joseon assassins sent by Minister Kim and other ministers, who are plotting a coup. The noise of the battle draws an attack by zombified villagers. Lee Chung and Hak-Su are assisted by local partisans, including Park Eul-ryoung, former lieutenant to the crown prince, and archer Deok-hee. The Jemulpo partisans ask Lee Chung to become crown prince, but he rejects the idea, wanting to return to China. Lee Chung awkwardly flirts with Deok-hee. The only survivor of the would-be assassins is captured by Kim because he is infected. The ministers arrange for a concubine to be infected. She later turns and infects the king. Lee Chung arrives at the king's court, where he requests an army with which to crush the zombies. The king initially agrees, but the ministers instigate him to rescind the order, claiming that there is no zombie outbreak, only a civil rebellion. The Jemulpo partisans are arrested, while Lee Chung and Gyeong-bin are ordered to attend a banquet for a visiting Qing delegation. At the banquet, the king fully turns into a zombie, and is slain by Kim, who unleashes zombies there in an attempt to kill members of the palace and the Qing delegation, then rule with all potential opposition gone. However, Kim is bitten by a zombie, leading to the ministers turning on each other in a mad bid for power. Only Kim survives; he chops off his own hand to slow the infection, then declares himself king. Gyeong-bin convinces Lee Chung not to flee, but to protect the people, so Lee Chung, the royal guard, and his Jemulpo allies freed from prison proceed to fight to prevent the zombies from escaping the palace and attacking the capital. Lee Chung and his allies make a plan to draw the zombies together into a gigantic fiery explosion at the palace. Kim kills Hak-Su and an infected Park, preventing the explosion. Lee Chung continues the same plan, battling a horde of zombies and the half-infected Kim, ultimately succeeding by using a flaming arrow from Deok-hee. Kim is slain by Lee Chung in a duel. Reinforcements of soldiers and commoners arrive to exterminate the rest of the zombies. Lee Chung recognizes that through the power of the people, the ruined Joseon has promise after all, and elects to stay rather than leave for Qing.