The film covers the life of Moses from his discovery in a basket floating on the Nile as a baby by Bithiah, a childless young widow and daughter of the then-Pharaoh, Rameses I, to his prohibition from entering the land of Israel in the wake of God's judgment on him at the waters of Meribah. In between, the film depicts the early adulthood of Moses as a beloved foster son of Pharaoh Seti I (brother of Bithiah) and general of his armies, his romance with Throne Princess Nefertari (or Nefretiri, as she is called in the film) and rivalry with the Pharaoh's own son, Prince Rameses II.
Shortly after Moses' birth, Rameses I had ordered the slaying of all firstborn male Hebrews to prevent the prophecy of the Deliverer from coming true. Moses' mother (called "Yoshebel" in the film) had set him adrift on the Nile to escape, with his sister Miriam watching from a hidden spot. Bithiah discovers the Ark while playing with other young women in the banks of the Nile. She orders them to leave, then shows her servant Memnet the baby. Memnet warned Bithiah that the swaddling cloth was Levite, so the baby was placed there to escape Bithiah's father's edict. But Bithiah declared that this baby would be her son, and remembered when the pyramids were dust, and named "Moses" because she had drawn him from the Nile (the Hebrew name "Moshe" derived from the Hebrew word "Mashu", meaning "to draw"). Despite Memnet's protests about serving a son of Hebrew slaves, Bithiah ordered her to serve him and to swear to secrecy on pain of death. But Memnet hides the cloth under her clothes.
As a young general, Moses is victorious in a war with the Nubian people of ancient Ethiopia, loosing captured ibises to combat the serpents (as recorded by Josephus) and further impresses Seti I by being wily enough to enter into an alliance with the conquered Ethiopians rather than subjugate them. Moses then is charged with building a treasure city for Seti's Jubilee, that Rameses failed to complete (probably the Biblical treasure cities of Pithom and Ramases (Avaris)).
Meanwhile, Moses and Nefretiri are deeply in love; she is the "throne princess", who must marry the next Pharaoh. Rameses wants her for himself, not because of any liking for her but for the throne, but Nefretiri hates him.
When Moses assumes control of the project, he rescued an old grease-woman from being left to be crushed; unknown to him it was his birthmother Yoshebel. Moses tells the Egyptian Master Builder Baka, "blood makes poor mortar" and asks "are you a master builder or a master butcher?" And he frees Joshua the stonecutter who had struck an Egyptian, punishable by death, to try to save Yoshebel whom Joshua didn't know. Moses was impressed with Joshua's bravery and words, and institutes numerous reforms concerning the treatment of the slave workers such as one day in seven to rest and even going so far as to raid temple granaries for necessary food supplies. Moses questions Joshua about his God, and Joshua declares his strong faith but says that God's name is unknown.
Rameses uses these changes as proof that Moses is planning an insurrection by currying the slaves' favor, and points out that the slaves are calling Moses the "Deliverer" of prophecy. However, when Seti confronts Moses, Moses argues he is simply making his workers more productive by making them stronger and happier. He proves his point with such impressive progress on the project that Seti becomes convinced that Rameses falsely accused his foster brother. Seti promises that Moses will get credit for the new city. Rameses, meanwhile, has been charged by his father with the task of finding out if there really is a Hebrew fitting the description of the Deliverer, and is having no luck.
As Nefretiri is joyously preparing for marriage, Memnet informs her that Prince Moses is not a prince at all, but the son of Hebrew slaves. Nefretiri is furious at the accusation, whereupon Memnet produces the Levite cloth and tells Nefretiri to wrap their firstborn in it. Memnet also tells her that a little girl had led her to Yochebel to breastfeed Moses, which she realized must be the real mother. Nefretiri kills Memnet by pushing her over the balcony.
Moses learns of this, so asks Bithiah, who dissembles and reminds him of how he never doubted her when he held his hand as he took his first step. When Moses leaves, promising that no matter what he found, he would always love her. She rushes in a chariot to Yoshebel. Bithiah pleads with her not to reveal anything, since she has put the throne of Egypt within his grasp, and also declares how much she loved and cared for him, and promised to free them and make sure they were well cared for. But Moses had followed from a distance, and Yoshebel could not look him in the eyes and deny that she was his mother. And her robe matched the pattern of the much more faded Levite cloth Memnet kept. Then Yoshebel's adult children introduce themselves to Moses as, "I am your brother, Aaron," and "I am Miriam, your sister." Bithiah sadly departs.
Declaring he is not ashamed ("Egyptian or Hebrew, I'm still Moses"), but curious, he spends time working among the slaves to learn of their hardship, only to be rescued from the mudpits by Nefretiri. Moses then saves Joshua, a Hebrew stonecutter, from being whipped death at the hands of Baka; he kills Baka who was about to whip Joshua to death. Dathan, the devious and ambitious Hebrew overseer who's been charged by Rameses to help him find the Deliverer, watches from hiding. Moses confesses to Joshua that he himself is Hebrew; Joshua excitedly proclaims Moses the Deliverer, and although Moses denies it, Dathan has all the proof he needs. Revealing what he knows to Rameses, Dathan bargains for Baka's house, a post as Governor of Goshen and the ownership of Joshua's betrothed Lilia.
Moses is arrested and brought in chains before Seti, who begs him to say he is not the Deliverer. Moses does so, but avows that he would free the slaves if he could. Bithiah confesses to her brother Seti that she took Moses from the Nile knowing by the design on his blankets that he was Hebrew. In a short, impassioned speech, Moses says that it is evil to enslave or oppress people, "to be stripped of spirit, and hope and faith, all because they are of another race, another creed. If there is a God, He did not mean this to be so!" Seti is grievously hurt, since he said that he had always loved him as a son, more than his own real son Rameses. So Seti imprisons him and orders his name stricken from all records and monuments, to be unspoken in Egypt forever thereafter. Rameses banishes Moses to the desert, fearing to execute him lest he create a martyr. Meanwhile, Seti proclaims Rameses to be the next Pharoah. Nefretiri as the Throne Princess is required to marry the arrogant prince, to her great distress.
Moses makes his way across the desert, nearly dying of hunger and thirst. He comes to a well in the land of Midian. After drinking and eating dates from a nearby palm tree he passes out, to be awakened by the sound of seven sisters watering their flocks. Bullying Amalekites appear, pushing the girls aside, whereupon Moses wakes. Seemingly appearing out of nowhere he thrashes the Amalekites soundly with his staff, forcing them to wait their turn at the well. Moses finds a home in Midian with the girls' father Jethro, a Bedouin sheik, who reveals that he is a follower of "He who has no name", which Moses recognized as the God of Abraham. Jethro explains that they are the descendants of Ishmael, Abraham's first-born. Moses later impresses Jethro and the other shieks with his wise and just trading, so Jethro offers Moses one of his daughters as a wife. Moses chooses the eldest daughter, called Sephora in the film (the Greek form of her name), the least flamboyant but wisest, who was previously the one who had stood up to the Amalekites.
Back in Egypt, Seti dies heartbroken, with Moses' name on his lips, and Rameses succeeds him as Pharaoh (becoming Rameses II), taking Nefretiri as his Queen. Herding sheep in the desert, Moses finds Joshua, who has escaped from hard labour in the copper mines. Moses sees the Burning Bush on the summit of Mount Sinai; climbing up to investigate, he hears the voice of God. Naming himself "I Am That I Am", God charges Moses to return to Egypt and free His chosen people.
At Pharaoh's court, Moses comes before Rameses to win the slaves' freedom, turning his staff into a snake to show Rameses the power of God. Jannes and another magician do the same, but Moses's snake eats the others (not shown; the small son of Rameses and Nefretiri tells his mother with alarm). But the Pharaoh decrees that the Hebrews be given no straw to make their bricks, but to make the same tally as before on pain of death. As the Hebrews prepare to stone Moses in anger, Nefretiri's retinue rescues him; but when she attempts to resume their relationship, he spurns her, reminding her that not only is he on a mission, having been touched by God, but that he is also married.
As Moses continues to challenge Pharaoh's hold over his people, Egypt is beset by divine plagues. We see the water turned into blood, and hear of others. But Rameses hears of a naturalistic explanation of a mountain beyond the Nile cataract spewing red mud, although this would not have explained what the film showed: the red colour starting from where Aaron's stick touched the river and moving away, or the water in pitchers turning red as it was poured. but given this explanation, Rameses declared it not surprising that fish would die and frogs leave the water, and flies would bloat upon their carcasses and spread disease. So Moses predicts hot hail and three days of darkness; the hot hail comes shortly after and bursts into flame on the ground. Moses warns that the next plague would come from his own lips.
Enraged at the plagues and Moses' continuous demands, and at his generals and advisers telling him to give in. Rameses orders all first-born Hebrews to die, but just as Moses had foretold, this intention backfires. Although Nefretiri warns Sephora to escape with Gershom on a passing caravan to Midian, Moses tells her sadly that it is her own son who will die, and he cannot save him. In an eerily quiet scene, the Angel of Death creeps into Egyptian streets in a glowing green cloud, killing all the firstborn of Egypt, including the adult son of Pharaoh's top general, and Pharaoh's own child. Meanwhile, Bithiah is released to Moses.
Broken and despondent, Pharaoh orders Moses to take "your people, your cattle, your God and your pestilence" and go. Dathan is also ordered out when the Egyptian guards sees the sacrifice lamb's blood on the sides of his door frame, his position as an overseer counting for nothing with the Egyptians, the Hebrews resentful of him and refusing him the privileges he expects. The Exodus of the Hebrews from Egypt begins.
Behold His mighty hand!Goaded into rage by Nefretiri in her grief and anger at Moses, the Pharaoh arms himself and gathers his armies to chase the former slaves to the shore of the Red Sea. Held back by a pillar of fire, the Egyptian forces can only watch as Moses parts the waters ("Behold His mighty hand!") to provide his people an escape route. As the Hebrews race over the seabed, the pillar of fire dies down and the army rides in hot pursuit. The Hebrews make it to the far shore just in time to witness God's closing of the waters on the Egyptian army, drowning every man and horse. Rameses looks on in despair. All he can do is return to Nefretiri, confessing to her, "His god is God."
The former slaves camp at the foot of Sinai and wait as Moses again ascends the mountain. When Moses delays coming down from Sinai, the Hebrews lose faith and, urged on by the evil Dathan, build a golden calf as an idol to bear before them back to Egypt, hoping to win Rameses' forgiveness. Aaron is forced to help fashion the gold plating. He also orders Lilia to be sacrificed. The people proceed to indulge their most wanton desires in an orgy of sinfulness. Sephora, now re-united with Moses, tells the people that he has gone to receive God's Law, and Bithiah asks, "Would the God who's shown you such wonders let Moses die before his work his done?" But their defences are mostly disregarded after Dathan's demagoguery.
Meanwhile, high atop the mountain, Moses witnesses God's creation of the stone tablets containing the Ten Commandments. When he finally climbs down, Moses beholds his people's iniquity and hurls the tablets at the idol in a rage. The idol explodes, and Dathan and his followers (such as Korah) are killed, a burning crevasse swallows all who do not join Moses at his side. After God forces them to endure forty years' exile in the desert wandering lost to prove their loyalty, the Hebrews finally are on the eve of arriving in the land of Israel. An elderly Moses then appoints Joshua to succeed him as leader (with Lilia by Joshua's side), says a final good bye to his devoted wife Sephora, and goes forth out of Israel to his destiny.