The Battle of the Labyrinth camp for the school year. On his fifteenth birthday at the summer's end, Percy receives a visit from his father Poseidon, who gives him a sand dollar, admonishing him to “spend it wisely”. Nico later appears to tell Percy his plan to defeat Luke once and for all. "The Battle of the Labyrinth" was initially referred to as "Percy 4" until the title was officially revealed. The novel was teased by Rick Riordan behind the pages of its predecessor, "The Titan's Curse". It was based on the Greek myth of the labyrinth, where the Minotaur was supposedly kept. In his
The Battle of the Labyrinth book opens with Percy Jackson attending freshman orientation at Goode High School, where he sees Rachel Elizabeth Dare, a clear-sighted mortal who helps him fight two empousai and escape. Percy travels to Camp Half-Blood, where he learns Grover is in trouble with the Council of Cloven Elders for not having found Pan. During a competition organized by the new sword instructor Quintus, Annabeth and Percy accidentally find an entrance into the Labyrinth, which presents a possible invasion route for Luke. Annabeth is given leadership of a quest to find Daedalus and convince the inventor not to give Luke Ariadne's string.