In this modern version of the Greek myth, Persephone asks Hades for a ride to escape her overprotective mother, sneaks into the Underworld, and refuses to leave.

Percy, expelled from six schools for being unable to control his temper, learns the truth from his mother that his father is the Greek god Poseidon, and is sent to Camp Half Blood where he is befriended by a satyr and the demigod daughter of Athena who join him in a journey to the Underworld to retrieve Zeus's lightning bolt and prevent a catastrophic war.