This article is about the event. For the book, see here.
The forces of Kronos army burst out of the Labyrinth from the entrance at Zeus' Fist in the forest and attacked the defenders. They encountered a myriad of traps set by the Hephaestus and Athena Cabins. However, their sheer numbers endured the succession of traps, and an overwhelming force of monsters and rival Demigods sparked the Battle of the Labyrinth. A climactic battle erupted, in which every camper, along with a few nymphs, fought. Just as the armies became even, Kampê joined the fray, causing the Titan army to gain the upper hand. Percy Jackson and Annabeth Chase unsuccessfully tried to fight Kampê. Meanwhile, Briares and Daedalus joined the fight, and Briares buried Kampe under a pile of rocks nearly as large as Zeus' Fist. Nico di Angelo summons some undead warriors to help and the effort nearly kills him. Despite their efforts, the camp was outnumbered. In a last desperate attempt, the monsters in the Titan Army made a last stand, in which Chiron's back leg was broken by a giant. Soon, Grover Underwood managed to stop the battle by causing a Panic, an ability from the god Pan that scared the entire army away, back into the Labyrinth.
- Castor – Son of Dionysus, stabbed and killed by an enemy demigod.
- Lee Fletcher – Son of Apollo, killed by a giant's club.
- Kampê – Buried under a pile of rocks by Briares.
- Daedalus – Let Nico release his soul to destroy the Labyrinth so Kronos' army can't get into the camp or use the Labyrinth.
- Other members of the Titan army.
Chiron knows the army will be back for another battle soon. Daedalus says it was wrong for him to hide from death for years, and that his death alone will destroy the Labyrinth and prevent a second invasion of the camp. Nico kills Daedalus by releasing his soul, causing the Labyrinth to collapse, as it is tied to his life force. The demigods burn shrouds as the proper funeral rites for those who died. When the Council of Cloven Elders tries to banish Grover, Dionysus steps in, vouches for Grover, and warns the Council not to argue with him because he had just learned of the death of his son Castor and consequently is in a very foul mood. As a side note, due to his son Castor's death, Dionysus asked Percy to make sure his other son, Pollux, doesn't die in battle in The Last Olympian.