Percy is a twelve-year-old boy from New York, with dyslexia and attention deficit disorder - at least that's what the experts say. After being expelled for the sixth time from his school, he discovers one day the truth about all the strange things happening to him.

In reality, he is a demigod, the son of a god and a mortal. . . But the worst part is that the gods are angry with him and have sent various monsters after him. Zeus's lightning has been stolen - the staff of lightning - and Percy is considered the prime suspect. This theft has sown discord among the gods and a Third World War seems more threatening than ever.

[Excerpt from the text on the back cover of the edition]