Pharaoh was afraid the Israelites will take over Egypt, just like the Hyksos did. He made the Israelites slaves and ordered for all male babies to be killed. Moses was sent away on a boat by his Israelite mother, and he was found and raised by the Pharaoh's daughter.
Moses knew he was an Israelite, and was upset about how his people were treated. He asked the pharaoh to let the Israelites leave Egypt, but the Pharaoh didn't want to lose his slaves. Moses cursed Egypt with 10 plagues, and finally the pharaoh agreed.
The Israelites left immediately, but the pharaoh changed his mind and sent his army after them. Moses parted the red sea and they walked to Canaan, and the Egyptians were washed away by the sea.