In Ancient Egypt, the enslaved Hebrew people pray to God for deliverance. Pharaoh Seti, fearing that the increase of Hebrew slaves could lead to rebellion, orders his guards to kill all newborn Hebrew boys. Fearing for her newborn son's safety, Yocheved and her other two children, Miriam and Aaron, rush to the Nile River, where she places him in a basket on the water, after bidding him farewell with a final lullaby. Miriam follows the basket as it sails to the Pharaoh's palace and witnesses her baby brother safely adopted by Seti's wife Queen Tuya, who names him Moses. Before leaving, Miriam prays that Moses will come back to them and set their people free.
Years later, Moses and his adoptive brother Rameses, heir to the throne of Egypt, are scolded by Seti for accidentally destroying a temple during a chariot race. At Moses's suggestion to give Rameses the opportunity to prove his responsibility, Seti names Rameses Prince Regent and gives him authority over Egypt's temples. As a tribute, high priests Hotep and Huy offer Rameses a beautiful young Midianite woman, Tzipporah. Rameses gives Tzipporah to Moses and appoints him Royal Chief Architect. Later that night, Moses follows Tzipporah as she escapes from the palace, and runs into the now-adult Miriam and Aaron, whom he does not recognize. Miriam then sings their mother's lullaby, triggering Moses's memory. He flees in denial, but learns the truth of Seti's genocide from a nightmare, then from Seti himself, who disturbs Moses by claiming the Hebrews were "only slaves". The next day, Moses tries to stop an Egyptian guard from whipping an elderly Hebrew slave, accidentally pushing the guard to his death. Horrified and ashamed, Moses flees into the desert in exile, despite Rameses's pleas that he stay.
Arriving at an oasis, Moses defends three young girls from brigands, only to find out their older sister is Tzipporah. Moses is welcomed by Jethro, Tzipporah's father and the high priest of Midian. Over time, Moses becomes a shepherd, falls in love with Tzipporah, and marries her. One day, while chasing a stray lamb, Moses discovers a burning bush, through which God tells him to return to Egypt and guide the Hebrews to freedom. God bestows Moses's shepherding staff with his power and promises that he will tell Moses what to say. When Moses tells Tzipporah of his task, she decides to join him.
Arriving in Egypt, Moses is happily greeted by Rameses, who is now Pharaoh with a wife and son. Moses requests the Hebrews' release and transforms his staff into a snake to demonstrate God's power. Hotep and Huy deceptively recreate this transformation, only to have their snakes eaten by Moses's. Not wanting to have his actions cause the empire's collapse, Rameses hardens and doubles the Hebrews' workload.
The Hebrews, including Aaron, blame Moses for their increased workload, disheartening Moses. However, Miriam inspires Moses to persevere. Moses casts the first of the Ten Plagues of Egypt, turning the water of the Nile into blood, but Rameses remains unmoved. Moses inflicts eight more plagues onto Egypt, but still Rameses refuses to relent, vowing never to release the Hebrews. Disheartened, Moses prepares the Hebrews for the tenth plague, instructing them to sacrifice a lamb and mark their doorposts with its blood. That night, the final plague kills all the firstborn children of Egypt, including Rameses's son, while sparing those of the Hebrews. Grief-stricken, Rameses gives the Hebrews permission to leave. After leaving the palace, Moses collapses in grief at the pain he has caused his brother and Egypt.
The following morning, the Hebrews, led by Moses, Miriam, Aaron and Tzipporah, leave Egypt. At the Red Sea, they discover that a vengeful Rameses is pursuing them with his army, intent on killing them. However, a pillar of fire blocks the army's way, while Moses uses his staff to part the sea. The Hebrews cross the open sea bottom; the fire vanishes and the army gives chase, but the sea closes over and drowns the Egyptian soldiers, sparing Rameses alone. Moses sadly bids his brother farewell and leads the Hebrews to Mount Sinai, where he receives the Ten Commandments.