The climax in Rick Riordan's "The Lightning Thief" comes when Percy Jackson is betrayed by his friend Luke, who confesses to working with Kronos to overthrow the Olympians. Percy is stung by a deadly scorpion but is saved and nursed back to health.
Percy Jackson is an average seventh grader with dyslexia who never fits in. His life changes when he learns that he is the son of Poseidon and is invited to attend Camp Half-Blood, which is a school for the children that the Olympic gods fathered.
While in school, Percy must learn to be a hero. He and his friends Annabeth and Grover, each the child of an Olympian, decide to find Zeus's master bolt, which he uses to make lightning, and stop a brewing war between Zeus and Poseidon. Their adventures take them to the Underworld, and along the way, they battle Medusa and go up against Ares, the god of war. Only after the three half-bloods escape the Underworld do they learn that Ares stole the master bolt and the symbol of Hades, the helm of darkness, in order to spark a war between Zeus and Poseidon.
Percy and his friends best Ares and return the master bolt and the helm of darkness. Percy tells his father and Zeus that he believes Kronos is behind the thefts. Neither god believes Percy, who returns to Camp Half-Blood to finish the school year. Here, he is betrayed by Luke, and at the end of the year decides to spend the summer break with his mother.