In the film, Percy Jackson, a sixteen-year-old teenager, discovers that he is the son of Poseidon, god of the seas, and is taken to Camp Half-Blood, a training site for demigods. When Percy's mother is kidnapped by Hades, and Percy is accused of stealing Zeus's master ray, he and his friends embark on a mission to rescue his mother from the Underworld, having to pass through North America first. in order to find Persephone's pearls and prove that Percy is not The Lightning Thief.
Already in the Sea of Monsters, this time, Percy Jackson, discovers that he has a half brother named Tyson, and embarks on another mission, this time, to find the Golden Fleece, in order to save his camp, which had its borders poisoned by Luke Castellan. In this tree, there is the spirit of Thalia, daughter of Zeus, who died on the border of the camp to save Annabeth, Luke and Grover. To find the fleece, they will have to travel through the Sea of Monsters, a place feared by all demigods.