When Camp Half-Blood, the only safe haven for demigods, comes close to being overrun by mythological monsters, Percy must find his best friend Grover, who is prisoner on an island in the Bermuda Triangle, and then set out to save the Camp.
After learning that the father he never knew is Poseidon, God of the Sea, Percy Jackson is transferred from boarding school to Camp Half-Blood, a summer camp for demigods, and becomes involved in a quest to prevent a war between the gods.
When demonic cheerleaders invade his high school, Percy Jackson hurries to Camp Half Blood, from whence he and his demigod friends set out on a quest through the Labyrinth, while the war between the Olympians and the evil Titan lord Kronos draws near.