In Japanese-occupied Korea in 1925, Chun Man-duk, a revered hunter, lives with his teenage son, Seok, in a hut near Mount Jirisan. Following a tragic accident in which he killed his beloved wife, he has retired his rifle and become a humble herb gatherer limping amongst his cherished mountains.
The Japanese governor-general overseeing the occupation gathers tiger pelts as a hobby of seeming cultural dominance, and soon becomes obsessed with killing possibly the last remaining tiger in Korea, an enormous one-eyed male that lives on the mountain and has killed scores of hunters.
The tiger is known locally in hushed tones as Mountain Lord, and locals fear its demise will bring wolves and boars return because of its absence. Gu-kyung is the resolute but ruthless leader of a band of Korean hunters that attempt to track and kill the tiger for the bounty, including by killing its mate and two cubs and using them for bait. Eventually, we learn that Man-duk mortally wounded the tiger’s mother when she leapt at him near her kill of an escaped barnyard animal during a winter of privation.
He saved the nearby one-eyed cub and its sibling by intervening against the more junior hunter Gu-kyung, who delivered the killing shot on their mother. He told them to leave them to their fate. It is revealed that he secretly relocated them to a safe den, though the sibling soon died. Seok loves a girl in town, and secretly joins one of Gu-kyung’s hunts in aspiration of earning a bounty sufficient to convince her father to allow them to marry; during the hunt, Seok wounds the tiger, but is himself mortally wounded.
After several failures, mounting hunter deaths, and facing deepening winter, soldiers of the Japanese army are dispatched to participate in escalating efforts to find and kill the tiger, and several attempts are made to enlist Man-duk to facilitate the hunt, all of which he resolutely resists. However, following Seok’s death and the wounding of the great beast, hunter and tiger, now both bereft of mates and offspring, each tread fatefully toward the snow-blasted mountain top, with the bounty hunters and army in close pursuit. Man-duk reaches the top of the mountain and waits for the tiger. Soon following, the tiger appears. Man-duk and the tiger then seem the fight, with the former injuring the tiger. Man-duk provokes the tiger, asking why he “stopped”, and proceeds to take out a knife at the mountain’s edge. The tiger pounces at him, and they both fall off the mountain together.
The governor-general of the Japanese army asks the hunters what happened after the incident, and they relate to him a story about the Mountain Lord becoming a god. The governor-general determined that they are unable to fight during the looming winter and have decided to withdraw until the next spring and proceeds to take his leave. The film ends with flashbacks of Man-duk’s and the tiger’s happier early lives and returning to the present where the bodies of the tiger and Man-duk are lying next to each other as the snow falls and cover their bodies.