Demi-god Percy Jackson and his friends must journey into the Sea of Monsters to save their camp. But first Percy will discover a secret that makes him wonder whether being claimed as Poseidon's son is an honor or a cruel joke.

Persephone was ready to start a new life when she left the mortal realm for Olympus. However, she quickly discovered the dark side of her glamorous new home--from the relatively minor gossip threatening her reputation to a realm-shattering violation of her safety by the conceited Apollo--and she's struggling to find her footing in the fast-moving realm of the gods. Hades is also off-balance, fighting against his burgeoning feelings for the young goddess...

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.