In 1900, American Ann Mercedes arrives in Cairo at the site of an archaeological dig and calls on Mark Brandon, who is in charge of the excavation. Ann explains that her late father, a famous archeologist, was searching for a tomb believed to contain proof that the Old Testament account of Joseph in Egypt was literally true. She produces a solid gold statuette from the 18th Dynasty, and Mark notes that it bears the inscription of the pharaoh Ra-Hotep, whose tomb has not officially been discovered. Ann replies that her father found it in London, along with other antiquities that had been smuggled out of Egypt, and declares her intention to finish her father's work. Drawn by her beauty and spirit, Mark agrees to help her, but is disappointed to learn that Ann has a husband who will be arriving in Egypt soon. Posing as a wealthy collector, Ann visits the antiquities shop of Valentine Arko, and persuades him to help her acquire stolen objects from Ra-Hotep's tomb. After she leaves his shop, however, Arko is confronted by Hamed Bachkour, who warns him to reveal nothing about the smuggling operation. Ann visits another shop and is shocked to learn that someone else had just inquired about Ra-Hotep's treasures. She and Mark go to her hotel, where they find Ann's husband Philip waiting for them. Philip, a smooth European whom Mark instantly distrusts, reveals that he was the one asking about items from Ra-Hotep's tomb in town. Mark, Ann and Philip encounter Father Anthimos, who suggests that they accompany him to St. Catherine's monastery in Sinai. In the monastery's burial tomb, Mark and Ann discover clay tablets indicating that Ra-Hotep's tomb is in the Valley of the Kings. Mark, Ann and Philip set out to find the tomb, but their search is in vain. One day, in Luxor, a strange man approaches Ann and takes her to see Arko, who offers to sell her information that will lead her to the tomb. Arko says that many years ago, a man named Campos, who has since been murdered, became wealthy overnight and was rumored to be smuggling antiquities out of Ra-Hotep's tomb. The merchant reveals that a man named Ahmed Salah worked as Campos' guide, and advises Ann to seek him in the nearby village of El Tabor. Arko also warns Ann that Bachkour, who could be the man behind the smuggling operation, might be staying at their hotel. That night, as Arko prepares to leave Luxor, Bachkour stabs him to death. Philip then appears from the shadows, and Bachkour thanks him for the information about Arko's whereabouts, adding that as his partner, Philip will receive ten percent of the price of the antiquities they smuggle to Europe. Philip pulls out a gun and threatens to tell the police about Arko's murder unless he receives half the contents of Ra-Hotep's tomb. The following day, Mark, Ann and Philip lead a search party, which includes Bachkour, on an arduous trek through the desert to El Tabor. After a ferocious sandstorm separates them from the others in the caravan, Mark and Ann are taken in by the nomadic Taureg tribe and meet Salah, who was left badly disfigured when Campos attempted to murder him. Salah bitterly challenges the Americans' claim that they seek Ra-Hotep's tomb for religious reasons, and according to tribal law, Mark is forced to fight a duel with Salah to prove he is telling the truth. Mark prevails and spares Salah's life. That night, Mark and Ann surrender to their growing attraction and kiss. In the morning, Salah leads Mark and Ann to the ancient temple where he had taken Campos. Mark surmises that the actual tomb of Ra-Hotep is elsewhere, but that the temple served as a hiding place for the grave robbers who raided the tomb thousands of years ago. Mark scales the walls of the temple and discovers Bachkour's body on a ledge. He then locates a secret passageway, where Philip is waiting with a gun. The two men fight, as Ann looks on in dismay, and Philip plunges to his death. Disheartened, Ann wants to abandon the expedition, but Mark reproaches her for her lack of faith and insists that they return to the Valley of the Kings. Mark and Ann organize a dig and eventually locate Ra-Hotep's tomb. Together they explore the burial chamber, and in a hidden room find evidence that the pharaoh embraced monotheism. They also find a statue of Joseph, confirming Ann's father's theory. Thrilled with their discovery, Mark and Ann look forward to their future together.
