When Zeus, Hades, and Poseidon continue on a new quest in the search for the Helm of Darkness, they discover many things in the Underworld that Hades does not fear except a giant three-headed dog.

In this modern version of Greek mythology, Hades, King of the Underworld, tells the true story of Theseus finding his way through the labyrinth to slay the Minotaur.

A near-death experience, a horrible incident at school, and a move from Connecticut to Florida have turned seventeen-year-old Pierce's life upside-down, but when she needs him most John Hayden is always there, helping but reminding her of her visit to the Underworld.

"Percy Jackson is about to be kicked out of boarding school ... again. And that's the least of his troubles. Lately, mythological monsters and the gods of Mount Olympus seem to be walking straight out of the pages of Percy's Greek mythology textbook and into his life. And worse, he's angered a few of them. Zeus's master lightning bolt has been stolen, and Percy is the prime suspect. Now Percy and his friends have just ten days to find and return Zeus's...

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.