What role does Annabeth play in The Lightning Thief?

A deuteragonist, Annabeth Chase is the demigod daughter of Athena. Because of her familial conflicts, she ran away at the age of seven before she stayed at Camp Half-Blood, a refuge for demigods. She helps Percy on his quest to retrieve Zeus' lightning bolt, using her intelligence to guide them to their destination. She is reported to have blonde hair and grey eyes, and is especially skilled with the dagger.