In the Old Testament book of Exodus, God calls the prophet Moses to lead the Hebrew slaves out of Egypt. When the Pharaoh refuses to let them go, Moses sends ten terrifying plagues into Pharaoh's land. The first six (red river water, droves of frogs, insects and disease) nearly destroy Pharaoh's city, but still he refuses to free the Hebrew slaves. Plagues seven, eight, and nine bring hail, locusts, and darkness. Then, the final mysterious 10th plague kills the firstborns of Egypt.