In the opening chapter of 'The Lightning Thief', we are introduced to Percy Jackson, a twelve-year-old boy who struggles with ADHD and dyslexia. The narrative begins with Percy recounting his experiences at Yancy Academy, a private school in New York, where he feels like an outsider. He is not only dealing with the usual challenges of being a young adolescent but also grappling with the knowledge that he is different from his peers.

During a school field trip to the Metropolitan Museum of Art, Percy and his classmates are supposed to be learning about ancient Greek artifacts. However, things take a dramatic turn when Percy finds himself in the company of a monstrous creature, which he later learns is a Fury, a mythological being sent to retrieve something from him. This encounter occurs when Percy’s emotional state is at a peak, as he faces bullying from a classmate and the looming pressure of his failing grades.

As the tension escalates, Percy discovers that he possesses extraordinary abilities, including the ability to summon water. In a moment of panic, he unintentionally creates a wave that helps him escape from the Fury. This event marks the first significant indication that he is not just an ordinary boy, but a demigod, specifically the son of Poseidon, a major Greek god.

The chapter emphasizes Percy's feelings of confusion and fear as he grapples with the reality of his situation. He begins to understand that his life is intertwined with the myths and legends he has heard, but he struggles to comprehend what this means for his identity. The chapter ends with Percy being taken away from the museum, deeply shaken by the revelation of the monster and the realization that his life is about to change drastically.

Overall, this chapter sets the stage for Percy’s journey, introducing the themes of identity and the supernatural while highlighting his internal conflicts. It effectively draws readers into Percy's world, where the ordinary clashes with the extraordinary, laying the groundwork for the adventures that are to come.