"In The Son of Neptune, Percy, Hazel, and Frank met in Camp Jupiter, the Roman equivalent of Camp Halfblood, and traveled to the land beyond the gods to complete a dangerous quest. The third book in the Heroes of Olympus series will unite them with Jason, Piper, and Leo. But they number only sixwho will complete the Prophecy of Seven? The Greek and Roman demigods will have to cooperate in order to defeat the giants released by the Earth Mother, Gaea....

They've sailed on the Santa Maria, defended famous cities from Vikings and Mongols, and come face to face with some of the greatest figures in history. Now, at long last, Dak, Sera, and Riq travel back in time to the moment it all began. Their mission: to save the life of young Alexander the Great. But they are not the only time travelers in ancient Greece. An epic battle against their most dangerous foe awaits them, and history will be written by...

Percy Jackson, a modern-day demigod, tells the stories of all the daring deeds of Perseus, Atalanta, Bellerophon, and the rest of the major Greek heroes.