Paris in 1850, Louis-Napoléon Bonaparte [Leon Ames] is the president of the French Republic. During a sunlit tennis match in Paris between Ferdinand de Lesseps [Tyrone Power] and his friend Vicomte Rene de Latour [Joseph Schildkraut], the radiant Countess Eugenie de Montijo [Loretta Young] captures the president’s gaze and sparks a whirl of political and romantic intrigue. At a grand reception, a fortune teller’s prophecy hints that Eugenie’s life will be troubled yet crowned, and that de Lesseps will dig a ditch—a curious omen that threads through the film’s ambitions and ambitions fulfilled. Enchanted by Eugenie, Bonaparte arranges for his rival to be sent away to a diplomatic post in Egypt, where he will join his father, Count Mathieu de Lesseps [Henry Stephenson], the Consul-General. The young man, Ferdinand, impulsively asks Eugenie to marry him on the spot, only to be gently refused.
In Egypt, de Lesseps begins to cross paths with two people who will steer his destiny: Toni Pellerin [Annabella], a tomboy raised by her grandfather, French Sergeant Pellerin, and Prince Said [J. Edward Bromberg], the indolent heir of Mohammed Ali, the Viceroy. Toni makes it clear she has fallen in love with him, even as de Lesseps remains fixated on Eugenie. The elder de Lesseps returns to France, leaving his son to carry the burden of the new opportunity and the family name.
One day, after a sudden desert rain, de Lesseps witnesses water draining toward the sea and conceives the audacious idea of a canal slicing through the Isthmus of Suez. He hurries back to Paris to gain backing, with Toni by his side. He presents the plan to Bonaparte, who rejects it, and he also learns that Eugenie’s heart has moved closer to the Emperor. The country tilts toward civil strife as Bonaparte’s faction clashes with the French Assembly, and de Lesseps—alongside Eugenie—is drawn into the political maelstrom. Eugenie persuades Ferdinand to carry Bonaparte’s proposal to the Assembly, urging them to disband and promising to reconvene once the unrest subsides. The Assembly agrees, but the move backfires: betrayal leads to arrests, and Bonaparte seizes power, declaring a revived empire. The news drives a fatal stroke through the elder de Lesseps, and Ferdinand, though outraged, is soothed by Toni’s counsel to stay the course. In a turn of political calculus, Napoleon III withdraws his objections to the canal, and construction begins under de Lesseps’ steady leadership.
The canal project advances even as Turkish saboteurs threaten its progress. Britain’s political maneuverings add further pressure: while the British Prime Minister remains openly opposed, the opposition leader Benjamin Disraeli becomes a champion of the project. Disraeli’s willingness to back the venture brings renewed funding, and the dream of a navigable link between seas gains new momentum. Prince Said, ever willing to stake everything, bankrupts himself to keep the project alive, but the struggle is far from over. De Lesseps travels to England to press his case, and with Disraeli’s backing the funding is secured, turning the dream of a canal into a working reality.
As the completion date nears, a brutal sandstorm roars across the desert, threatening to erase all the progress made. Toni rescues de Lesseps by securing him to a wooden post, but in the chaos she is swept away and killed. With grit, ingenuity, and the support of Eugenie—who has become Empress through her marriage to Napoleon III—the canal is finished, and de Lesseps is celebrated as a man who turned a daring vision into a monumental achievement.
