* He needs to find his missing mother: He believes that Hades, the god of the Underworld, has kidnapped his mother, Sally Jackson. He needs to find her and bring her back.
* He wants to understand the situation: Percy wants to know more about the Underworld and Hades' motivations for kidnapping his mother. He wants to understand the conflict and how to potentially resolve it.
* He's looking for answers: Percy is confused and scared. The world he thought he knew has been turned upside down. He's desperate for answers, for someone who can explain what's happening and how to stop it.
Chiron, being the wise and knowledgeable centaur, is the only one Percy feels he can trust to answer his questions and guide him on his journey.