In 1184 France, in a secluded village, the blacksmith Balian (Orlando Bloom) grapples with the haunting grief of his wife's recent suicide. A group of Crusaders arrives, including one who introduces himself as Balian's father, Baron Godfrey of Ibelin (Liam Neeson). Godfrey implores Balian to journey with him back to Jerusalem, but Balian declines, prompting the Crusaders to depart.
Adding to his torment, the town priest, Balian's half-brother, reveals a horrifying truth: he ordered that Balian's wife be beheaded before burial, a cruel custom for those who take their own lives. In anger, Balian confronts his brother, kills him in a fit of rage, retrieves the cherished cross that belonged to his wife, and flees the village. Driven by a quest for forgiveness and redemption for both himself and his wife, Balian tracks down Godfrey in hopes of a new beginning.
However, tension escalates as Godfrey's nephew leads soldiers to arrest Balian, with ulterior motives to kill them both to claim Godfrey's barony. Godfrey, refusing to abandon Balian, faces the nephew's treachery and eventually kills him, but not without sustaining a fatal arrow wound.
In Messina, Godfrey knights Balian, commanding him to protect the King of Jerusalem and foster peace between Christians and Muslims before he succumbs to his injuries. As Balian sets sail to Jerusalem, a storm wrecks his ship, and he finds himself as the sole survivor alongside a horse. He releases the horse, but it bolts away in fear. Chasing after it, Balian encounters a Muslim cavalier and his servant, and in a desperate struggle, he inadvertently kills the cavalier while sparing the servant, who offers to guide him to Jerusalem.
Upon arrival, Balian learns the significance of his actions; he unwittingly becomes famous among the Saracens, the Muslim warriors who lay claim to Jerusalem. Navigating the treacherous political landscape, he becomes acquainted with key figures such as the leper King Baldwin IV (Edward Norton), Tiberias (Jeremy Irons), Princess Sibylla (Eva Green), and her ambitious husband Guy De Lusignan (Marton Csokas), whose dark aspirations threaten to plunge the region into chaos.
As Sibylla develops feelings for Balian, their relationship deepens within the walls of his barony, where he works tirelessly to improve the land’s irrigation. Meanwhile, Guy and Raynald of Chatillon (Brendan Gleeson) commit a horrifying massacre of a Muslim trade caravan, provoking retaliation from Saladin (Ghassan Massoud), the formidable leader of the Muslim armies. Balian, determined to protect the villagers taking refuge in Kerak, makes a valiant stand against overwhelming odds, leading to his capture but ultimately garnering Saladin's respect for his bravery.
The political fabric of the kingdom frays as Baldwin confronts Raynald, forcing him to his knees, leading to the King’s deteriorating health. A proposal arises for Balian to marry Sibylla, knowing their mutual affection, but he refrains, conflicted by his principles and the violent implications it entails.
As Sibylla's son is tragically diagnosed with leprosy and succumbs to a dire fate, the vicious cycle of violence escalates. Guy, now King, embarks on a path of war, leading to the brutal execution of Raynald and the impending assault on Jerusalem. Despite the attrition, Balian remains to protect the town’s residents as chaos brews on the battlefield.
After a harrowing three-day conflict with Saladin's forces, Balian ultimately negotiates the surrender of Jerusalem, securing the safety of its people in the process. In a poignant farewell, Sibylla renounces her claim, and Balian returns to his origins as a blacksmith in France. When King Richard I of England (Iain Glen) rides in seeking Balian, the former blacksmith humbly insists he is no longer a knight but merely a smith, signaling the beginning of another daunting chapter in their saga. Together with Sibylla, they ride toward an uncertain future, filled with new possibilities.
