Mrs. Dodds transforms into a winged Fury and attacks Percy at the museum; Mr. Brunner throws Percy a pen that becomes a sword.

Percy secretly overhears Mr. Brunner and Grover discussing a summer solstice deadline and their concern about keeping Percy alive.

Grover arrives at Percy's beach vacation during a terrible storm to warn Percy that monsters are coming for him.

The Minotaur attacks Percy's group on the road to Camp Half-Blood and seizes Percy's mother, who dissolves into golden light.

Percy kills the Minotaur by stabbing it with its own broken horn, then drags Grover across Camp Half-Blood's boundary.

Chiron climbs out of his wheelchair disguise to reveal he is a centaur and explains that the Greek gods are real and active.

A glowing trident appears above Percy's head during Capture the Flag, and Chiron announces Percy is the son of Poseidon.

Chiron tells Percy that Zeus believes Percy stole his master lightning bolt and demands its return by the summer solstice.

Percy visits the Oracle in the camp attic and receives a cryptic prophecy about traveling west and being betrayed by a friend.

Three Furies board Percy's bus looking for him, and the confrontation causes the bus to crash and explode.

Percy decapitates Medusa with Riptide at her garden gnome shop after she attempts to turn the group to stone.

Ares gives Percy a backpack of supplies and reveals that Percy's mother is alive and being held hostage.

Percy opens Ares's backpack inside Hades's palace and discovers Zeus's stolen lightning bolt hidden inside.

Percy uses three magical pearls to escape the Underworld with Annabeth and Grover, leaving his mother behind with Hades.

Luke confesses he stole the lightning bolt for Kronos, then flees Camp Half-Blood after leaving Percy with a scorpion bite.

Percy Jackson, a boy who has been expelled from school after school, discovers he is a son of the sea god Poseidon after a series of monster attacks leads him to Camp Half-Blood. Zeus accuses Percy of stealing his master lightning bolt and threatens war if it is not returned by the summer solstice, launching Percy on an urgent quest across America. With his friends Annabeth Chase and the satyr Grover, Percy battles monsters and navigates help from gods and spirits as they close in on the Underworld. In Hades's palace, Percy discovers the bolt was secretly planted in his backpack by Ares, who was himself manipulated by the imprisoned Titan Kronos. Percy escapes the Underworld, defeats Ares on a California beach, and returns the bolt to Zeus on Mount Olympus, narrowly preventing a divine war. The identity of the real thief is finally revealed when Percy's fellow camper Luke confesses he stole the bolt for Kronos before poisoning Percy and fleeing the camp.

The quest to find and return Zeus's stolen lightning bolt.

Percy loses control and unknowingly manipulates a water fountain to defend Grover from a classmate's bullying at the museum.

Percy and Grover spot three old women knitting by the highway; one cuts her yarn and Percy fears someone will die.

Percy's mother surprises him with a spontaneous beach vacation after his expulsion, giving them a rare weekend together alone.

Percy is assigned to Cabin 11, home of Hermes's children and unclaimed campers, until his divine parent is identified.

Clarisse drags Percy to the bathroom to dunk his head in a toilet, but Percy floods the entire room and drives her off.

At his first camp dinner, Percy watches every camper toss a portion of their food into a fire as an offering to the gods.

Grover tells Percy that after World War II, the Big Three swore on the River Styx to father no more demigod children.

Percy moves out of Cabin 11 and into Poseidon's empty Cabin 3 alone after being formally claimed as Poseidon's son.

Luke presents Percy with a pair of winged sneakers as a gift from Hermes; Percy passes them along to Grover instead.

Echidna and her chimera attack Percy inside the Gateway Arch elevator after posing as a harmless woman and her small dog.

Trapped and out of options atop the Gateway Arch, Percy prays to Poseidon for the first time and jumps into the Mississippi River.

Percy, Annabeth, and Grover spend five days inside the Lotus Hotel without noticing any time has passed at all.

A Nereid meets Percy at the Santa Monica beach and presents him with three magical pearls sent by Poseidon.

Annabeth distracts the three-headed dog Cerberus using a rubber ball from dog obedience class, allowing the group to slip past.

Percy returns home after his quest and tearfully reunites with his mother, who Hades sent back safely.

Before arriving at Camp Half-Blood, Percy shows early signs of his powers by unknowingly controlling water at the museum and witnesses the Fates cutting a thread of life on a highway overpass. His mother takes him on a final peaceful beach trip before monsters close in, and once at camp Percy navigates its social landscape, making an enemy of Clarisse and beginning to settle into life among fellow demigods. Percy learns about the strict oath the Big Three swore after World War II and is claimed as a forbidden son of Poseidon, moving into an isolated cabin alone. On the quest westward, Percy faces escalating dangers including a chimera attack at the Gateway Arch before being ensnared by the time-warping Lotus Hotel, losing five precious days. The Nereid delivers Poseidon's pearls at the Santa Monica shore, and Annabeth's quick thinking with a rubber ball allows the group to slip past Cerberus at the Underworld's gate. After the quest is completed and the threat neutralized, Percy comes home to find his mother safely returned, and the two share a tearful reunion.

Camp Half-Blood, the journey west, and Percy's reunion with his mother.

Percy is expelled from Yancy Academy after snapping at a teacher, setting the events of his summer in motion.

Grover reveals to Percy that he is a satyr and that all the Greek myths from Mr. Brunner's class are real.

Percy wakes at Camp Half-Blood and meets Annabeth Chase, the camp director Mr. D, and Chiron for the first time.

Annabeth explains to Percy that if his divine parent is powerful enough, he may be forced to live at camp permanently.

Percy angrily packages Medusa's severed head and mails it to Mount Olympus as an act of defiance against the gods.

Grover confesses his previous failed mission that cost Thalia her life and explains that Percy's quest is his absolute last chance.

Percy dreams of a sinister presence in a dark pit that offers to return his mother if he brings it the lightning bolt.

During an IM call to camp, Luke speculates the bolt's thief must have been invisible, indirectly implicating Annabeth.

Annabeth tells Percy that no matter which side the gods choose in a war, she will always fight on Percy's side.

Percy discovers he can communicate with a zebra on an animal-smuggling truck, revealing his Poseidon-given ability to speak to horses.

Percy realizes he cannot remember his mother's name inside the Lotus Hotel, alerting him that something is deeply and magically wrong.

Grover's winged sneakers activate on their own and drag him toward the pit of Tartarus before falling off his hooves.

Hades reveals that his helm of darkness has also been stolen and accuses Percy of taking both powerful godly items.

Percy wounds Ares in a beach battle and realizes that the voice from the pit had been manipulating Ares all along.

Percy warns Zeus that Kronos is regaining power in Tartarus and orchestrated the entire theft, but Zeus forbids further discussion and vanishes.

Percy's expulsion from school sets off a chain of revelations that upend his understanding of the world, beginning when Grover confesses he is a satyr and that everything from Mr. Brunner's Greek mythology class is real. At Camp Half-Blood, Percy learns that a powerful godly parentage could permanently exile him from the mortal world, and on the road west he starts receiving dream communications from a sinister presence in a dark pit. Key turning points on the quest include Percy's defiant act of mailing Medusa's head to Olympus, the Lotus Hotel escape triggered by Percy forgetting his own mother's name, and Luke's suspicious remark about a thief who must have been invisible. In the Underworld, the revelation that Hades's helm was also stolen and that the winged sneakers were designed to drag Percy into Tartarus exposes how deeply Kronos had planned the entire scheme. Percy wounds Ares and understands clearly that Kronos orchestrated events by manipulating both gods and demigods alike, yet when Percy tries to warn Zeus about Kronos's growing power, Zeus shuts the conversation down and departs, leaving the threat unresolved.