Percy, expelled from six schools for being unable to control his temper, learns the truth from his mother that his father is the Greek god Poseidon, and is sent to Camp Half Blood where he is befriended by a satyr and the demigod daughter of Athena who join him in a journey to the Underworld to retrieve Zeus's lightning bolt and prevent a catastrophic war.

"Athena isn't the only new kid at Mount Olympus! When a mortal named Heracles transfers to the Academy, Athena understands what he's going through. She started there a few months ago herself. Not only does Heracles need help fitting in, he also has to complete twelve 'labors' or be kicked out of school!"

When demonic cheerleaders invade his high school, Percy Jackson hurries to Camp Half Blood, from whence he and his demigod friends set out on a quest through the Labyrinth. Meanwhile the war between the Olympians and the evil Titan lord Kronos draws near.

Athena learns that she is a goddess when she is summoned to Mount Olympus by her father, Zeus, and she must quickly adjust to her new status, make friends with the other godboys and goddessgirls, and catch up with all the studies she missed while attending mortal school.

While protecting egotistical transfer student Orion, Artemis makes a mistake that later provides her with the chance that she has both hoped for and dreaded, to prove her courage to herself and others at Mount Olympus Academy.

The Greek god Apollo is still in the persona of ungifted human teenager Lester Papadopoulos. Now Lester and his demigod friends must go through the Labyrinth to find the third emperor-- and an Oracle who speaks in word puzzles-- somewhere in the American Southwest. But the longer he stays mortal, the weaker he grows... and the less confident that he will be able to regain his place on Mount Olympus.

Will the Greek god Apollo, cast down to Earth in the pathetic mortal form of a teenager named Lester Papadopoulos, finally regain his place on Mount Olympus? Lester's demigod friends at Camp Jupiter just helped him survive attacks from bloodthirsty ghouls, an evil Roman king and his army of the undead, and the lethal emperors Caligula and Commodus. Now the former god and his demigod master Meg must follow a prophecy uncovered by Ella the harpy. Lester's...

The long-awaited prophecy surrounding Percy Jackson's sixteenth birthday unfolds as he leads an army of young demigods to stop Kronos in his advance on New York City, while the Olympians struggle to contain the rampaging monster, Typhon.