The Percy Jackson books by author Rick Riordan are a successful series that started in 2005. The books follow the tales of a demigod (one parent is a god, the other mortal), Perseus "Percy" Jackson, who is the son of Poseidon. The series has become increasingly popular over the years, so it makes sense that a film adaptation of the series would be attempted.
In the film Percy Jackson (Logan Lerman) is a boy living with his mom Sally (Catherine Keener) and step-dad Gabe (Joe Pantoliano), who Percy doesn’t get along with. He has never met his real dad. He hasn’t had an easy life and it’s about to get worse as Zeus’s (Sean Bean) master lightning bolt has been stolen. Zeus tells his brother Poseidon (Kevin McKidd) that Percy is responsible; Poseidon says his son is innocent, but Zeus doesn’t care and demands the bolt be returned by midnight on the summer solstice which arrives in 14 days or war will begin between the Olympians.
Percy has had protectors watching over him his entire life in secret, but when a Fury attacks him on a school trip, his protectors know he must be moved to safety. Percy then learns his best friend Grover (Brandon T. Jackson) is a satyr and his Latin teacher Mr. Brunner (Pierce Brosnan) is a centaur and the duo decide to move him to Camp Half-blood.
Camp Half-blood is where demigods live and train, and Brunner is the camp trainer. However once Percy is at camp, Hades makes his presence known by telling Percy he has taken Sally prisoner and will free her if Percy gives him the lightning bolt. Percy then meets Annabeth (Alexandra Daddario) daughter of Athena, and Luke (Jake Abel), son of Hermes.
Percy needs to get to the underworld, rescue his mom, and get out. Getting in isn’t a problem, but leaving will be. Luke tells Percy about the pearls Hades’ wife Persephone (Rosario Dawson) has placed around the country so she can have “visitors” without her husband’s knowledge.