Percy Jackson's stepfather had killed Sally Jackson, Percy's mom, and then Percy ran away from home as he saw that Gabe was going to kill him next. He made it to the sea and jumped into the water and swam to a cave. There he was almost eaten by a great white but she saw the fear, sadness, and loneliness in Percy's eyes. The female shark, Named Sheila, took Percy in and taught him the ways of the sea.