Plot

Percy Jackson is a twelve year old boy diagnosed with and , who has been expelled from several schools. On a trip with his mother, his friend Grover, revealed to be a , urgently tells Percy's mother that Percy must go to a certain camp. As they drive towards camp, they are attacked by a which grabs Percy's mother. She dissolves into a golden shower of light, while Grover and Percy narrowly escape.

Percy wakes up and discovers that he has arrived in Camp Half-Blood, a secretive training ground for . Thereafter, Percy is moved into the cabin under the care of Luke, the Cabin counselor. During a game, Percy is attacked by the children of Ares. He heals when he steps into the adjoining river and is revealed as the son of when Poseidon's trident appears above his head. Poseidon had broken an oath taken with Hades and Zeus after of not having any more children since they were too powerful. Percy is then granted a quest to find Zeus's master bolt which Chiron believes Hades has stolen. However, Zeus, who discovered Poseidon had broken his oath, believes Poseidon had Percy steal the bolt. Percy, who has ten days before summer solstice to find the bolt, is given magic shoes by Luke before leaving. Percy, accompanied by Annabeth and Grover, decide to travel west to reach the entrance to the in . They encounter several Greek monsters, and also the war god, , who tells Percy that his mother is alive. As they approach the pit of , Luke’s shoes try to pull Grover into it, but he manages to slip free his hooves. Percy confronts Hades who also believes Percy stole the Master Bolt as well as his . Percy realizes that Ares has tricked him when he discovers the bolt in his backpack. He flees from the Underworld, forced to leave his mother. Percy then fights and defeats Ares by hurting the god's heel. Ares gives Percy the Helm of Darkness which Percy returns to Hades. Percy reaches New York City to give the master bolt to Zeus at the top of where Olympus is now located. Zeus accepts the master bolt and thereafter Percy returns to camp, after learning that his mother is alive. He meets Luke, who reveals that he stole the bolt for . He calls out a poisonous scorpion which stings and nearly kills Percy. Chiron cures him and Percy leaves to attend another school found by his mother.

Major characters

• : The protagonist; a twelve year old boy who has been diagnosed with as well as . Percy discovers that he is the son of Greek god and that his disabilities are natural for , also known as half-bloods. He embarks on an adventure to find Zeus's master lightning bolt to prevent a disastrous war among the gods.
• : A twelve year old daughter of the goddess . Annabeth was brought to by and . She helps nurse Percy after he is attacked by the . She also accompanies Percy on his quest to find Zeus's master bolt. Annabeth has been going to Camp Half-Blood since she was seven and possesses a necklace that has beads from every year she survives at Camp Half-Blood.
• : Grover is a and Percy's best friend. Initially, he was undercover as a boy in search of potential demigods. He leads Percy to the Camp after his mother is taken and accompanies him on his journey to find Zeus's master bolt. His lifelong dream is to find the god of wild places, .
• : The main antagonist and a son of ; he is the counsellor of the Hermes cabin and helps train Percy in the art of battle. Later, he betrays Percy and leaves him for dead, revealing that he works for the Titan .
• : He is, at first, Percy's teacher, Mr. Brunner. Later, Percy discovers he is a , half-horse and half-man. He is Camp Half-Blood's Activity Director.