Plot
As the book opens, Jason awakens on a school bus, unable to remember who or where he is, or anything about his past. He is sitting next to Piper McLean and Leo Valdez, who call him by name and say they are his girlfriend and best friend respectively. All three are part of a class field trip to the Grand Canyon, and after they arrive, a classmate Dylan turns into a Venti (Storm Spirit) and attacks the trio and their trip leader, Coach Gleeson Hedge. In the ensuing fight, Jason surprises everyone, including himself, when one of his coins turns into a sword which he uses to battle the storm spirits. Coach Hedge, who reveals himself to be a satyr during the fight, is taken captive by a fleeing spirit. After the battle, a flying chariot arrives to rescue the trio, but one of the people in it, Annabeth, is upset when she discovers that her missing boyfriend, Percy Jackson, is not there as she expected. Annabeth, seeking Percy, was told in a vision from the goddess Hera to look there for the "guy with one shoe", but this turns out to be Jason, who had a shoe destroyed during the fight.
Jason, Piper, and Leo are told that they are demigods and are taken back to Camp Half-Blood where they meet other Greek demigod children like themselves. There, Leo is revealed as a son of Hephaestus, Piper as a daughter of Aphrodite and Jason as a son of Zeus, though Hera tells him he is her champion. Jason later discovers that he is the full brother of Zeus's demigod daughter Thalia Grace, who is a Hunter of Artemis. Shortly after they arrive, the three are given a quest to rescue Hera, who has been captured, and they set off. They soon discover that their enemies are working under orders from Gaea to overthrow the gods. During their quest, they encounter Thalia and the Hunters, who have been looking for Percy. Thalia and Jason reunite for the first time since Jason was captured at the age of two by Hera.
On the way to Aeolus's castle,