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.

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.