The Battle of the Labyrinth recap

Percy learns that Daedalus's Labyrinth has an entrance inside Camp Half-Blood, so Luke's army could invade from within. Annabeth leads a quest, with Percy, Grover, and Tyson, into the maze to reach the inventor Daedalus before the enemy can obtain the means to control it. In the shifting maze they meet gods and monsters, cross paths with Nico, a son of Hades shadowed by a manipulative ghost, and seek Hephaestus, who sends Percy into a volcano. Blown clear, Percy washes up on Calypso's island before choosing to leave and is found to have been presumed dead. The mortal Rachel Elizabeth Dare, who sees through the Mist, guides them to Daedalus, who has been living at camp as the instructor Quintus. Grover finds the dying wild god Pan, who passes on his work. When Luke's army invades through the maze, Daedalus dies to collapse it, and the camp holds. Kronos completes his return by taking over Luke's body, and Nico shares a plan for the war ahead.

Previously: Percy Jackson, demigod son of Poseidon, trained at Camp Half-Blood with his friends Annabeth, a daughter of Athena, and Grover, a satyr, and gained a Cyclops half-brother, Tyson. His old camp friend Luke betrayed the gods to serve the reviving Titan lord Kronos. On a quest west, Percy helped free the goddess Artemis and trap the Titan Atlas beneath the sky, but lost the Hunter Zoe and a young half-blood, Bianca di Angelo. Bianca's brother, Nico, blaming Percy for her death, fled and revealed himself as a son of Hades, able to command the dead. Thalia, a daughter of Zeus, joined the Hunters, leaving a prophecy about a child of the eldest gods pointing toward Percy as war with the Titans looms.

At high school orientation, Percy is helped by a mortal girl, Rachel Elizabeth Dare, who can see through the Mist, and fights off demon attackers before fleeing to camp. There a new sword instructor named Quintus has appeared with a friendly hellhound, and Percy and Annabeth discover that an entrance to Daedalus's Labyrinth, the ancient maze, lies within the camp's borders, meaning the enemy could invade from within. Percy also witnesses Nico, now a son of Hades who can raise the dead, being guided by a scheming ghost toward a bargain to restore his sister. To keep the enemy from mastering the maze, a quest is given to Annabeth to find Daedalus first.

Annabeth leads Percy, Grover, and Tyson into the ever-shifting Labyrinth. Inside they meet gods and monsters, free an ancient hundred-handed creature whom Tyson befriends, and again cross paths with Nico, who is pursuing his own grim errand. They defeat a three-bodied giant on his ranch and seek out the smith-god Hephaestus for guidance. Hephaestus agrees to help only if Percy first investigates who has been intruding on one of his volcano forges, sending Percy off toward a dangerous confrontation while the others continue searching for the inventor.

Investigating the forge beneath a mountain, Percy unleashes a burst of destructive power against the enemy's servants and is thrown clear as the volcano erupts. He washes up on the hidden island of the nymph Calypso, who heals him and offers him a peaceful life there, but he chooses to leave and return to his friends. Percy discovers he was gone long enough to be presumed dead. Needing a guide who can navigate the deceptive maze by sight, the questers bring in the mortal Rachel, whose clear vision can lead them where magic misleads.

Guided by Rachel through the maze, the group reaches the workshop of Daedalus and learns that the inventor, kept alive for ages by moving his mind into automaton bodies, has been living at camp disguised as Quintus. He holds the key to controlling the Labyrinth that both sides want. Meanwhile Grover at last finds the lost wild god Pan, deep within the maze. Pan is fading as the world's wild places dwindle; at peace, he entrusts his work to Grover and the others before dying, ending an age for satyrs and nature spirits.

Luke's Titan army invades Camp Half-Blood through the Labyrinth. In the battle the defenders hold at a cost, and Daedalus, choosing to end his long life, dies in a way that collapses the maze and permanently closes the enemy's shortcut into the camp. The gravest development is the enemy's: the Titan lord Kronos completes his return by fully taking over the body of Luke, who has surrendered himself to his master, so the coming war will be led by Kronos wearing a demigod's form. Percy goes home for his birthday to find his mother happily involved with a kind mortal teacher, and Nico shares with him a dangerous plan for how he might stand against Kronos when the final war arrives.

Luke's Titan army invades Camp Half-Blood through the Labyrinth, and in the battle the inventor Daedalus, having helped the defenders, chooses to end his long life; his death collapses the maze and permanently cuts off the enemy's shortcut into the camp, though the fighting costs demigod lives. The lost wild god Pan has died deep in the maze after entrusting his work to Grover and the others, marking the end of an age for satyrs and nature spirits. Percy returns home for his birthday, where his mother, Sally, is now happily involved with a kind mortal teacher, Paul Blofis. The gravest turn is the enemy's: the Titan lord Kronos completes his return by fully taking over the body of Luke, who has given himself to his master, so the coming war will be led by Kronos in a demigod's form. Nico di Angelo, reconciled somewhat with Percy, reveals a dangerous plan for how Percy might stand against Kronos when the final conflict comes. The great prophecy about a child of the eldest gods now points squarely toward Percy as his sixteenth birthday nears.