Percy Jackson: The Battle of the Labyrinth, Book Four, by Rick Riordan

OPercy and riptide of anaklusamos and kronos coffin

After being attacked by empousai cheerleaders at his new school, Percy returns to Camp Half-Blood and learns about the Labyrinth, part of the palace of King Minos in Crete that, according to Greek mythology, was designed by Daedalus. He also meets the camp's new sword master, Quintus, who is later revealed to be Daedalus. During a game against giant scorpions at the camp, Annabeth and Percy accidentally find an entrance into the Labyrinth. Percy soon learns that Luke had used this entrance before and will try and lead his army through the Labyrinth straight in to the heart of Camp Half-Blood. i would rate it 5/5 choclate bars