Leo discovers a secret cave at camp half blood and he finds a dragon made out of metal. He fixes it up and uses on the mission. He can make things randomly appear, control metal, make stuff, and has a rare fire power. Leo is traumatized by thinking that he killed his mother when he was young but it really wasn't his fault. Hera has tormented Leo since he was a baby and she still does. He isn't very excited about freeing her. Even though Jason has amnesia he knows he doesn't belong in camp half blood. He later discovers that his sister is Talia. Piper has the gift of charm speak. Her dad is a famous actor. They are part of a prophesy of 7 demigods that are supposed to try to save Olympus from Gaea and the Giants. On the mission they are attacked by cyclopes, encounter a King Midas, and meet Medea. When they encounter Medea they discover that their teacher Coach Hedge is still alive.
They are all supposed to be dead. The Underworld is starting to bring back people and monsters that should be dead and monsters don't stay dead. They can materialize instantly. They also visit Aneomi the wind God to help find the Wolf house where the Goddess Hera is being held. They find the wolf house and free Hera, and stop the rise of the leader of the giants. Gaia is trying to awaken and if that happens it's bad super bad. The 3 of them stop the awakening of her for now.