Percy Jackson is a twelve year old boy diagnosed with ADHD and dyslexia, who has been expelled from several schools. On a trip with his mother, his friend Grover, revealed to be a satyr, urgently tells Percy's mother that Percy must go to a certain camp. As they drive towards camp, they are attacked by a Minotaur which grabs Percy's mother. She dissolves into a golden shower of light, while Grover and Percy narrowly escape.
Percy wakes up and discovers that he has arrived in Camp Half-Blood, a secretive training ground for demigods. Thereafter, Percy is moved into the Hermes cabin under the care of Luke, the Cabin counselor. During a Capture the Flag game, Percy is attacked by the children of Ares. He heals when he steps into the adjoining river and is revealed as the son of Poseidon when Poseidon's trident appears above his head. Poseidon had broken an oath taken with Hades and Zeus after World War II of not having any more children since they were too powerful. Percy is then granted a quest to find Zeus's master bolt which Chiron believes Hades has stolen. However, Zeus, who discovered Poseidon had broken his oath, believes Poseidon had Percy steal the bolt. Percy, who has ten days before summer solstice to find the bolt, is given magic shoes by Luke before leaving. Percy, accompanied by Annabeth and Grover, decide to travel west to reach the entrance to the Underworld in Los Angeles. They encounter several Greek monsters, and also the war god, Ares, who tells Percy that his mother is alive. As they approach the pit of Tartarus, Luke’s shoes try to pull Grover into it, but he manages to slip free his hooves. Percy confronts Hades who also believes Percy stole the Master Bolt as well as his Helm of Darkness, which is an object that allows him to become a shadow. This lets him sneak up on his opponents. Percy realizes that Ares has tricked him when he discovers the bolt in his backpack. He flees from the Underworld, forced to leave his mother. Percy then fights and defeats Ares by hurting the god's heel. Ares gives Percy the Helm of Darkness which Percy returns to Hades. Percy reaches New York City to give the master bolt to Zeus at the top of Empire State Building where Olympus is now located. Zeus accepts the master bolt and thereafter Percy returns to camp, after learning that his mother is alive. He meets Luke, who reveals that he stole the bolt for Kronos. He calls out a poisonous scorpion which stings and nearly kills Percy. Chiron cures him and Percy leaves to attend another school found by his mother.
