After discovering a secret that makes him question the honor of being the son of Poseidon, demi-god Percy Jackson journeys into the Sea of Monsters in an attempt to save Camp Half-Blood.
After learning that he is the son of a mortal woman and Poseidon, god of the sea, twelve-year-old Percy is sent to a summer camp for demigods like himself, and joins his new friends on a quest to prevent a war between the gods.