The Lightning Thief recap

Twelve-year-old Percy Jackson discovers that the Greek gods are real and that he is a demigod, the son of the sea god Poseidon. After a monster attack seems to kill his mother, he reaches Camp Half-Blood, a training ground for the gods' children. When Zeus's master lightning bolt is stolen, Percy is blamed, and to prevent a war among the gods he sets out with his friends Annabeth and Grover to find the true thief before the summer solstice. Their journey across the country toward the Underworld's entrance in Los Angeles pits them against monsters and gods, including Ares, who deceives them. In the Underworld Percy learns the bolt has been planted in his own bag and that his mother is held captive; he escapes but must leave her behind. He defeats Ares, returns the bolt to Mount Olympus, and stops the war. He then learns the real thief was his camp friend Luke, secretly serving the reviving Titan lord Kronos. Percy comes home to find his mother freed and chooses to spend the school year in the mortal world.

Twelve-year-old Percy Jackson keeps getting expelled from schools for bizarre incidents he cannot explain. On a class trip to a museum, one of his teachers transforms into a winged monster and attacks him, and afterward everyone insists she never existed and was never his teacher. His anxious friend Grover behaves strangely, and his Latin teacher, Mr. Brunner, seems to know more than he admits. At home Percy is caught between his loving mother, Sally, and his crude, unpleasant stepfather, Gabe. Sensing danger, Sally takes Percy to a seaside cabin, where Grover catches up to them and reveals that monsters are hunting Percy. A bull-headed creature attacks on the road; Percy's mother is seized and vanishes in a flash of gold, and Percy kills the monster before collapsing at the border of a mysterious camp.

Percy wakes at Camp Half-Blood, a hidden haven for the children of the Greek gods, who turn out to be real and still active in the modern world. Mr. Brunner is revealed to be Chiron, an immortal centaur, and the camp is overseen by the sour god Dionysus. Percy meets other young demigods, including the clever Annabeth, the friendly counselor Luke, and the hostile Clarisse, and learns that a camper's godly parent is often unknown. During a game of capture the flag, Percy's power over water surfaces and he is publicly claimed as a son of Poseidon, a forbidden birth under an oath among the most powerful gods. Chiron then reveals that Zeus's master lightning bolt has been stolen and Percy is being blamed; to head off a war among the gods, Percy accepts a quest to recover it, with suspicion pointing toward the Underworld far to the west.

Percy sets out west with Annabeth and Grover toward Los Angeles, where an entrance to the Underworld is said to lie. Vengeful monsters pursue them at every turn: the winged Furies attack aboard a bus, and at a roadside garden statuary shop they narrowly kill Medusa, whose gaze turns victims to stone. At the Gateway Arch in St. Louis, Percy is cornered by the fire-breathing Chimera and its mistress; badly hurt, he escapes by plunging into the Mississippi River, where he discovers he can breathe and heal underwater. The travelers press on, low on money and time, racing against a summer-solstice deadline before the gods go to war.

As they continue across the country, the travelers encounter the god Ares, who strikes a bargain with them: in exchange for aid he sends them to retrieve his shield, which leads them into a trap in an abandoned amusement park that they barely escape. They pass through the Lotus Hotel and Casino in Las Vegas, a place where time stands still and guests forget to leave, and only just break free after realizing that days have slipped by and their deadline is closing. Reaching Los Angeles at last, Percy outwits a monster running a waterbed store and finds the hidden entrance to the Underworld.

Percy, Annabeth, and Grover cross the river of the dead and reach the palace of Hades. There Percy discovers, to his horror, that the stolen master bolt has been hidden in his own backpack without his knowledge, and Hades furiously accuses him of also stealing his helm of darkness. Percy finds his captured mother held in the Underworld, but with only three magic escape pearls for four people, he is forced to leave her behind to save his friends and complete the quest. Escaping to a beach, the three are met by the god Ares, who is revealed to have set Percy up and arranged for the bolt to be planted on him. Percy defeats Ares in a duel with his sea powers, forcing him to return Hades' helm, and recovers the master bolt.

Percy flies to New York and climbs to Mount Olympus, returning the master lightning bolt to Zeus and averting war among the gods. He meets his father, Poseidon, who acknowledges him though the two remain distant. Back at Camp Half-Blood, Percy learns the deeper truth: the theft was meant to turn the gods against each other, and the real thief was Luke, the friendly counselor, secretly working for the reviving Titan lord Kronos, who wants to destroy the gods. Luke tries to kill Percy with a venomous scorpion before escaping to serve Kronos. At home, Percy finds his mother alive and freed from her cruel husband Gabe, whom she has turned to stone with Medusa's head. Given the choice to live at camp year-round, Percy decides to spend the school year at home with his mother, knowing that greater dangers, and Kronos, still lie ahead.

Percy recovers Zeus's master bolt, defeats the god Ares in single combat using his powers over water, and returns the bolt to Mount Olympus, averting war among the gods; he also forces the return of Hades' stolen helm of darkness. Meeting his father Poseidon face to face, Percy is acknowledged, though the two remain distant. Back at Camp Half-Blood he learns that the entire theft was engineered to set the gods against one another, and that the real thief was Luke Castellan, the counselor who had befriended him, secretly serving the reviving Titan lord Kronos, who seeks to overthrow the gods. Luke tries to kill Percy with a venomous scorpion and then flees to continue serving Kronos. Percy's mother, released from the Underworld, frees herself from her cruel husband Gabe by turning him to stone with Medusa's severed head. Offered the chance to stay at camp year-round, Percy instead decides to live at home and attend school with his mother, keeping a foot in the mortal world. The threat of Kronos and Luke's betrayal remains open for the books to come.