The Battle of the Labyrinth

The Battle of the Labyrinth, is the fourth book of the Percy Jackson and The Olympians series written by Rick Riordan.

Plot
The book begins with Percy going to a freshmen orientation class at Goode High School, a school where Paul Blofis, his mom's boyfriend, teaches. While there, he meets Rachel, a clear-sighted mortal whom he met previously at the Hoover Dam in The Titan's Curse, and is attacked by two Empousai, Tammi and Kelli. Percy slays Tammi, but Kelli got away. Unfortunately, Paul Blowfish and some freshmen saw the incident. Percy and Rachel escape through a broken window, and Percy, along with Annabeth, make their way to camp.

After arriving in camp, Percy stops by the arena and sees "the biggest hellhound he's ever seen", Mrs. O'Leary. He tries to stab her, but is soon parried by Quintus, the new sword-master, who reveals that Mrs. O'Leary is his pet. Chiron comes over and picks up Percy. He drops him next to Annabeth, Clarisse and a crying nymph, Juniper. Percy soon figures out that Grover has only one week to find Pan, the lost God of the Wild. Percy rushes over to clean up his cabin for the cabin inspection. As soon as he reached the Poseidon cabin, he sees his half-brother, Tyson, cleaning up. Tyson hugs him and has fixed his broken shield, the one he broke last winter during the fight with the manticore, Dr. Thorn.

Later, in a camp game designed by Quintus, Annabeth and Percy were attacked by three giant scorpions, and find an entrance to the Labyrinth, a magical underground maze, under Zeus's Fist within the heart of the camp. In a dream, Percy finds out that Luke plans to use the Labyrinth entrance to invade Camp Half-Blood.

Annabeth leads a quest with Percy, Grover and Tyson to find Daedelus, the maze's creator. Grover believes he can also find Pan somewhere in the Labyrinth. In the Labyrinth, they come across the minor god Janus, the Queen of Olympus Hera, and they also rescue an ancient Hundred-Handed One, Briares, from Kampê.

They then meet Nico di Angelo at the Triple G Ranch. After defeating Geryon, a triple-chested monster, at the ranch, they continue on their way, parting paths with Nico, who makes amends with Percy. Once back in the Labyrinth, the foursome match wits with a Sphinx. They then split up when Grover claims he can hear Pan calling to him. After a meeting with Hephaestus, Annabeth and Percy go searching for monsters that are invading the forge god's territory, which is also Mt. St. Helens. Before battling the half-dog, half-sea lion monsters called telekhines, Annabeth kisses Percy because she believes that Percy may die. Percy summons water from within himself to defeat the monsters, but the resulting explosion sends him to a phantom island called Ogygia. Percy encounters a girl named Calypso, who is a daughter of Atlas, and a Titan. Calypso falls in love with Percy, but Percy leaves her when he learns that Camp Half-Blood is in danger. With the help of Calypso, he gets back to camp by sailing on a magical raft.

Percy realizes that he knows a mortal who knows the way through the Labyrinth, so he, Annabeth, and Rachel go back to the Labyrinth and go look for Daedalus' workshop and for Grover and Tyson. They find Nico, while they battle Minos, Kelli and some giants that try to attack Daedalus. Rachel, Percy, Annabeth and Nico use pairs of golden wings to escape, leaving Daedalus, who stays to help Mrs. O'Leary. Percy then opens Kronos' sarcophagus and finds Luke's body. This means that Kronos is back and has fused his own and Luke's forms. Percy tries to run from Kronos and Rachel throws a hairbrush at the Titan's face. Luke yells in pain, but Kronos comes back into control as they escape.

The four then find Grover and Tyson, who find Pan, and watch Pan as he dies. Then, the five of them leave Rachel in the city, go back to camp, and fight in a war between the monsters and the campers. With the help of a terrible cry emitted from Grover, the monsters retreat from the battle, and then Percy goes home. Poseidon arrives for Percy's fifteenth birthday so Percy could explain everything to him. Poseidon tells Percy he is his favorite son before leaving. For his birthday, he calls Tyson to his house and Nico comes too. Nico says that he knows how to beat Kronos. The book ends at a cliffhanger as Percy tells Nico, "Come in and have some cake and ice cream. Sounds like we've got a lot to talk about."

Prophecy
This book's prophecy is given to Annabeth Chase instead of Percy:

You shall delve in the darkness of the endless maze,

''The dead, the traitor, and the lost one raise. ''

You shall rise or fall by the ghost king's hand, 

''The child of Athena's final stand. ''

Destroy with a hero's final breath, 

''And lose a love to worse than death. ''

Unraveling the Prophecy
Each line's meaning in order:
 * 1) Annabeth and her group going into the Labyrinth.
 * 2) Nico raising the dead (the dead), Ethan joining Kronos after Percy saves his life (the traitor), and Pan (the lost one).
 * 3) Nico announcing himself as the Ghost King, and he chooses to save Percy and Annabeth's lives.
 * 4) Daedalus' decision on whose side to be on.
 * 5) Daedalus willing the die for the Labyrinth's destruction (both being connected to each other)
 * 6) And Luke gives his body to Kronos.

At first, Annabeth was scared when she got the prophecy, thinking the fourth and fifth line was about her, not Daedalus. Though, she continued with the quest.

Chapter list

 * 1) I Battle the Cheerleading Squad
 * 2) The Underworld Sends Me a Prank Call
 * 3) We Play Tag with Scorpions
 * 4) Annabeth Breaks the Rules
 * 5) Nico Buys Happy Meals for the Dead
 * 6) We Meet the God with Two Faces
 * 7) Tyson Leads a Jailbreak
 * 8) We Visit the Demon Dude Ranch
 * 9) I Scoop Poop 
 * 10) We Play the Game Show of Death
 * 11) I Set Myself on Fire 
 * 12) I Take a Permanent Vacation
 * 13) We Hire a New Guide
 * 14) My Brother Duels Me to the Death
 * 15) We Steal Some Slightly Used Wings
 * 16) I Open a Coffin
 * 17) The Lost God Speaks
 * 18) Grover Causes a Stampede
 * 19) The Council Gets Cloven
 * 20) My Birthday Party Takes a Dark Turn

Main Characters

 * Percy Jackson - Main protagonist (son of Poseidon), helps Annabeth on her quest in the labyrinth. Percy also receives Mrs O'Leary, the hellhound at end of the book.
 * Annabeth Chase - Daughter of Athena. Annabeth receives the quest from the Oracle and becomes the owner of all Daedalus inventions on one of his silver laptops at the end of the book.
 * Rachel Elizabeth Dare - A mortal that can see through the mist. She is also Percy's friend.
 * Grover Underwood - A Satyr, and also Percy's best friend. Hates underground places. Becomes a Lord of Wild and a Chosen One of Pan. Grover also receives the cry of Pan after he dies which he uses to scare off Luke and his army.
 * Juniper- Tree nymph. Also, Grover's girlfriend.
 * Tyson - A friendly Cyclops who is a half brother to Percy.
 * Daedalus - Son of Athena, inventor, and creator of the Labyrinth. In the end he is revealed to be Quintus and committed suicide to stop Luke and his army in the Labyrinth because the Labyrinth is tied to his life force.
 * Nico di Angelo - Son of Hades and brother of Bianca di Angelo. In the last book he blamed Percy for his sister's death but forgives Percy while in the Labyrinth.
 * Luke Castellan- Son of Hermes, and becomes the host of Kronos at the end of the book.
 * Kronos- Rises in the end of the book, possessing Luke.

Monsters

 * Tyson - Percy's half brother and a good cyclops
 * Briares - the remaining Hekatonkheires
 * Kampe
 * Telekhines
 * Sphinx
 * Geryon - killed by Percy in a duel when Percy uses a bow and arrow
 * Empousai (Kelli and Tammi)
 * Typhon (Not actually seen)

Deaths

 * Antaeus - Stabbed by Percy
 * Castor - Son of Dionysus/ Mr. D, killed by an enemy half-blood.
 * Daedalus - He had Nico declare his death to destroy the Labyrinth.
 * Kampe - Briares buried her in rocks.
 * Kelli - Stabbed by Annabeth.
 * Lee Fletcher - Son of Apollo, killed by a giant's club.
 * Pan - Faded because of the pollution to his territory.
 * Tammi - Stabbed by Percy
 * Many unknown monsters