The story follows Percy Jackson, a 12-year-old boy who discovers that he is actually a demigod—the son of Poseidon, the Greek god of the sea. After being accused of stealing Zeus’s powerful lightning bolt, Percy is forced to go on a dangerous quest to clear his name and prevent a war between the gods. Along the way, he is joined by his friends Annabeth Chase and Grover Underwood. Together, they face mythological monsters, uncover hidden truths about Percy’s identity, and travel across the United States to reach the entrance to the Underworld.