Percy Jackson, a student with dyslexia and ADHD, is being expelled from Yancy Academy .Before he left, he mysteriously destroyed his pre-algebra teacher Mrs. Dodds. Oddly enough, nobody in the Academy recalls of Ms. Dodds after Percy destroys her. Percy and his mom go to spend a weekend in a cabin at Montauk. When his best friend Grover shows up, revealing himself as a satyr, everything starts to go wrong. His mother suddenly cancels their vacation and rushes to Camp Half-Blood, which Percy does not yet know about.
The Minotaur suddenly appears during the trip, wrecks their car, and makes Percy's mother dissolve leaving her in the Underworld, but eventually Percy defeats it and carries an unconscious Grover to camp. At Camp-Half Blood, where the children of Greek gods and mortals live, called demigods, Percy is faced with many challenges. He finds out that his Latin teacher is actually Chiron from Greek mythology He gets a new rival (Clarisse, daughter of Ares), and is officially claimed as the son of Poseidon. He is then offered a quest, which requires him to travel from New York City (where he lives) to Los Angeles. He goes on the quest with Grover and Annabeth, a daughter of Athena.