Moses was an underdog before he was even born. The Pharaoh of Egypt was killing all the male children of the Hebrew slaves because their population and strength was getting out of hand. Moses should have been killed as a child. His mother hid him.
Moses went from a slave child struggling to survive to a palace brat under Pharaoh's protection. Pharaoh's daughter found Moses where his mother has hidden him and adopts the child as her own. It is one of the great "underdog" stories.
As Moses's story unfolds, we see our hero is primarily an instrument of God to deliver His people from bondage. The deliverance of Israel is the center of the story. That is why the book is called Exodus not Moses.
Why is the deliverance of Israel, an underdog nation, so important to God's plan? The life of Moses gives us some insights into that question. His struggle with leadership, faith, and survival is a microcosm of Israel's struggle. As we get to know Moses we get to know Israel. Israel gives us a better understanding of Jesus and, of course, as we know Jesus better we know where we stand with God. There is nothing more important than our relationship with Him.