The gods of Olympus are alive in the 21st Century. They still fall in love with mortals and have children who might become great heroes, but by the age of twelve most of these children meet horrible fates at the hands of monsters. Only a lucky few learn the truth of their identity and make their way to Half Blood Hill, a summer camp dedicated to training young demigods. Such is the revelation that launches young Percy Jackson on a quest to help his real father, Poseidon, avert a war among the gods. With the help of Grover the satyr and Annabeth the daughter of Athena, Percy journeys across the US to catch a thief who has stolen the original weapon of mass destruction - Zeus' master bolt. Along the way, they must face a host of mythological enemies. Most of all, Percy must come to terms with a father he has never known, and an Oracle that has warned him of betrayal by a friend.