The Titan's Curse recap

Percy, Annabeth, and Thalia join Grover to bring two powerful half-blood siblings, Nico and Bianca di Angelo, to safety, but the school's vice principal is a manticore. Annabeth is captured, the Hunters of Artemis arrive, and Bianca joins them. Artemis leaves to hunt an ancient monster and is captured. The Oracle sends a quest, led by the Hunter Zoe Nightshade, to rescue the goddess and find Annabeth. Percy follows uninvited. Traveling west they face many dangers; in a desert junkyard, Bianca dies stopping a giant automaton. At a western mountain they find Artemis tricked into holding up the sky and the enemy general revealed as the Titan Atlas, allied with Luke, who holds Annabeth. Percy takes the sky's weight to free Annabeth, Artemis is freed and forces Atlas back under it, and Zoe dies in the battle. On Olympus the gods spare Percy. Thalia joins the Hunters, escaping the looming prophecy, and Nico, learning his sister is dead, flees and is revealed to be a son of Hades.

Previously: Percy Jackson, demigod son of Poseidon, learned that the Greek gods are real and trained at Camp Half-Blood alongside his friends Annabeth, a daughter of Athena, and Grover, a satyr. He stopped a war among the gods, then recovered the Golden Fleece to heal the poisoned tree guarding the camp. The Fleece worked so powerfully that it restored Thalia, a daughter of Zeus who had died and been turned into that tree, back to life. Behind these troubles is Percy's old camp friend Luke, who betrayed the gods to serve the reviving Titan lord Kronos. A prophecy hangs over the children of the three eldest gods, Zeus, Poseidon, and Hades.

Percy, Annabeth, and Thalia travel to a boarding school in Maine to help Grover bring in two unusually powerful half-blood siblings, Nico and Bianca di Angelo. The vice principal turns out to be a manticore serving the enemy's general, and in the fight Annabeth is captured and carried off. The Hunters of Artemis appear and drive the monster away, and Bianca chooses to leave her brother and join the Hunters. The goddess Artemis, sensing an ancient and dangerous monster on the move, departs to track it alone. Back at camp, the Oracle delivers a prophecy and a quest is formed to rescue the goddess, who is soon captured, and to find Annabeth, with the Hunter Zoe Nightshade set to lead it.

Before the quest departs, Nico makes Percy promise to keep his sister Bianca safe. Forbidden to go, Percy follows the questers west with the help of a pegasus. The travelers are hunted at every turn by monsters and the enemy's forces, defeating the Nemean Lion in Washington and pressing on across the country. The goddess Aphrodite appears to Percy along the way with cryptic interest in his fate. The group learns more about the mysterious monster Artemis pursued and races westward toward where the goddess is being held.

Crossing a desert, the questers enter a junkyard of discarded divine artifacts, where a giant bronze automaton comes to life. Bianca sacrifices herself to shut it down from the inside and is killed, a devastating loss that Percy feels he failed to prevent. Pursued by relentless skeleton warriors that reassemble when destroyed, the survivors cross the Hoover Dam, where animated statues come to their aid. Battered and grieving, they close in on the Titans' rising stronghold in the west.

At a mountain fortress the heroes find Artemis tricked into holding up the sky, and the enemy's general revealed as the Titan Atlas, working with Luke, who has captured Annabeth. Percy takes the sky's crushing weight upon himself to free Annabeth, and Artemis retakes the burden just long enough to force Atlas back beneath it. In the battle Zoe Nightshade is mortally wounded, fighting the guardian dragon and her own father, Atlas. She dies of her injuries and is set among the stars as a new constellation.

The survivors are carried to Olympus for the winter council of the gods, where the monster Artemis hunted proves to be a rare creature whose sacrifice could give power to destroy the gods; it is placed under protection instead of killed. The gods debate whether Percy is too dangerous to live and narrowly spare him. Rather than turn sixteen and become the likely subject of the great prophecy, Thalia joins the Hunters of Artemis and becomes ageless, shifting the prophecy's weight toward Percy. Nico, learning that Bianca died on the quest, blames Percy for breaking his promise and flees; as he goes, the dead rise at his call, revealing him as a son of Hades. Luke has survived, and the Titans' war draws nearer.

At the western mountain fortress, the heroes free the goddess Artemis, who had been deceived into shouldering the sky in place of the Titan Atlas. Percy briefly bears that crushing weight himself to free Annabeth, and Artemis retakes it long enough to trap Atlas beneath it once more. Zoe Nightshade, mortally wounded by the dragon guarding the enemy and by her own father Atlas, dies and is placed among the stars as a constellation. The rare monster Artemis had been hunting turns out to be a creature whose sacrifice could grant power to destroy the gods, and it is taken into protection rather than killed. On Olympus the gods debate whether Percy is too dangerous to live and narrowly choose to spare him. Thalia, rather than turn sixteen and become the likely subject of the great prophecy, joins the Hunters of Artemis and becomes ageless, which shifts the prophecy's burden toward Percy. Nico di Angelo, learning that his sister Bianca died on the quest, blames Percy for breaking his promise and runs away; as he does, the dead rise at his command, revealing him as a son of Hades. Luke has survived, and the Titans' war draws closer.