Jason wakes up on a school bus with no memory of his past. He is with Piper and Leo, two classmates who soon discover they are also demigods.
They arrive at Camp Half-Blood, where Jason learns he is the son of Jupiter (the Roman form of Zeus). The gods are in danger, and Hera has been kidnapped.
Jason, Piper, and Leo are sent on a quest across the United States to rescue Hera. Along the way, they face monsters and powerful enemies connected to Gaia, the Earth goddess who is rising against the gods.
They succeed in saving Hera, but a much bigger war is coming, and Jason’s lost memories remain a mystery.