Nico, the son of Hades, and his boyfriend Will, the son of Apollo, travel to Tartarus, the deepest, darkest part of the Underworld, as they attempt to rescue an old friend.
When demonic cheerleaders invade his high school, Percy Jackson hurries to Camp Half Blood, from whence he and his demigod friends set out on a quest through the Labyrinth, while the war between the Olympians and the evil Titan lord Kronos draws near.
Percy Jackson's hope for a normal senior year is shattered as the gods present him with three quests, beginning with the retrieval of Zeus's goblet, in order to get the necessary three letters of recommendation for college.