The disappearance of the goddess Artemis while out hunting a rare, ancient monster, prompts a group of her followers to join Percy and his friends in an attempt to find and rescue her before the winter solstice, when her influence is needed to sway the Olympian Council regarding the war with the Titans.

Based on the publishing phenomenon, Percy Jackson and other young demigods continue to fight, but this time in the sea, to fulfill their destinies. To save their world, Percy and his friends must find the fabled and magical Golden Fleece. Embarking on a treacherous odyssey into the uncharted waters of the Sea of Monsters (known to humans as the Bermuda Triangle), they battle terrifying creatures, an army of zombies, and the ultimate Evil.

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.

"The Greek and Roman demigods will have to cooperate in order to defeat the giants released by the Earth Mother, Gaea. Then they will have to sail together to the ancient land--Greece itself--to find the Doors of Death"--Provided by publisher.