Leaving the safety of the demigod training ground, a disgraced Apollo embarks on a quest across North America to find a dangerous ancient-world Oracle while navigating the challenges of the evil Triumvirate.

Greek and Roman demigods Nico, Jason, Reyna, Leo, and Piper try to stop Gaea, the Earth Mother, who needs the blood of two demigods sacrificed in Athens--the blood of Olympus--to awaken. Meanwhile, the friends keep having frightening visions of a great war at Camp Half-Blood that could be the end of all of them.

Uniting with Jason, Piper and Leo after the dangerous quest in "The Son of Neptune," Percy, Hazel and Frank wonder who will be chosen to fulfill the Prophecy of Seven, completing their group's number, and sail with them to an ancient land to find the mysterious Doors of Death.

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.

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's arrogance throws a wrench into her plans to improve King Minos's labyrinth.

"Medusa wants to be more like her two sisters and the other kids at Mount Olympus Academy -- immortal. Is that too much to ask? As one of the few mortals at MOA, it's hard not to get jealous when you're surrounded by beautiful, powerful goddessgirl and godboy classmates. And it isn't easy making friends either, especially when you have snakes for hair and one mean reputation!"--Amazon.

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.

In order to fit in at Mount Olympus Academy, new girl and forest-mountain nymph Echo copies the mannerisms of all the other students, but instead of ingratiating herself to her classmates, it only seems to grate on them.

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.