Temujin [Omar Sharif] grows up under a storm of violence after a rival Mongol faction led by Jamuga tortures him, his father is slain, and a wheel is locked around his neck as other children torment him. He meets the beautiful Bortai [Françoise Dorléac], but the grown danger of Jamuga follows him relentlessly. Temujin escapes and hides high in the hills, trailed by the holy man Geen and the mute Sengal, who pledge their loyalty to him. With a fierce resolve, he vows to unite all the Mongol tribes and forge a single, formidable people. The young warlord’s first bold moves see him freeing Salkit prisoners from a Merkits raid, who then join Temujin’s growing band and align with his Yesugei clan.
Raids along caravan routes swell the nascent army, and Temujin takes a decisive step to bind his fate to Bortai as his wife. His triumph is not without struggle: Jamuga locates Temujin’s camp, recaptures Bortai, and brutalizes her, only for Temujin to reclaim her and raise the resulting child as his own. With Bortai’s brothers defecting, Temujin’s drive to reunite the Mongol tribes intensifies, and his forces head east to escape Jamuga’s pursuit.
Kam Ling, a stranded Chinese ambassador [James Mason], is aided by Temujin and travels with him into Song China. In the capital, Temujin is treated to luxuries—fine clothing, baths, wine, and the arts—but the merciful facade masks a deeper truth: the Emperor fears letting the Mongols roam free inside China. After the Mongols defeat Manchurians led by Jamuga, Jamuga is captured, and the Emperor proclaims Temujin as Genghis Khan, the Prince of Conquerors. The Mongol army trains within Beijing for a long period, while Jamuga refuses to bring the Merkit tribes into Temujin’s united realm.
Temujin confides a longing to return the Mongol tribes to their homeland, but the Emperor resists, revealing a plan to keep them under Chinese oversight. Kam Ling quietly warns Temujin that only a Merkit could kill him, and Temujin deduces Jamuga is the intended assassin. An attempted quiet assassination becomes a dramatic escape when the Mongols trick the Emperor into lighting the final festival fireworks, which tear down a city gate and allow a breakout. They seize the Emperor’s daughter and Kam Ling, and begin a sweeping conquest of Asia. Temujin commands Bortai’s brothers—Jebi, Subotai and Kassar—to push campaigns across China, Russia, and India, respectively, as the momentum of the conquest grows.
The Mongols push from Manchuria toward Moscow, while Jamuga flees to the Shah of Khwarezm [Eli Wallach], winning his support for a new alliance with the Merkits. On the battlefield, Temujin’s envoy Kam Ling is killed after Jamuga refuses to join the united Mongols. With cannons from China, the Mongols break the Shah’s resistance, and Jamuga murders him in retreat. Jamuga then challenges Temujin to a duel and is slain in single combat, gravely wounding Temujin in the process. The Merkits bow before the Mongol leader, joining the newly united tribes. Temujin declares that his dream is realized: the Mongol peoples are one, even as he succumbs to his wounds after bidding farewell to Bortai and her brothers.
A closing voiceover notes Genghis Khan’s enduring legend and the lineage of his successors, including Babur, who would found the Mughal Dynasty of India, and Kublai Khan, who would become Emperor of China.
