There is a battle, as Kronos' army attacks Camp Half-Blood through the Labyrinth. Many are injured and some are left dead. Daedalus shows up to help along with his giant pet hellhound, Mrs. O'Leary. Daedalus has escaped death for centuries, but gives himself over to Nico di Angelo, a son of Hades, so he can accept his punishment in the Underworld and also so he can see his son Icarus and his nephew Perdix. Percy inherits Mrs. O'Leary; they have grown fond of each other. Percy and Annabeth's relationship starts to take on a new edge to it. Annabeth saves Percy several times and kisses him once because she thinks he is going to die. She also makes a big scene in front of all the campers when she realized that Percy was alive.