Jason Grace wakes on a school bus with no memory, flanked by two friends — Piper and Leo — who believe they know him. The three soon discover they are demigods, children of the Olympian gods, swept into a desperate quest to rescue a captured deity. Alongside this new trio, the world of Camp Half-Blood collides with the long-hidden Roman camp, Camp Jupiter, in a collision of traditions and loyalties that will define the series.

The Heroes of Olympus features an ensemble of seven demigods rather than a single lead, each carrying a different divine parent, a different power set, and a different emotional burden. Percy Jackson returns from the previous series as a beloved anchor; new leads Jason, Piper, Leo, Hazel, and Frank each carry full arcs. Leo Valdez in particular became a fan favorite for his humor hiding real pain.

Across five books, two camps worth of young demigods are forced to cooperate aboard the flying ship Argo II as the earth mother Gaea stirs toward wakefulness and her giants rise across the world. The ensemble of seven — Jason, Percy, Piper, Annabeth, Leo, Hazel, and Frank — each face their own fears and prophecies while racing to prevent a sacrifice in Athens that would wake Gaea permanently. The series melds action-comedy with genuine grief and sacrifice.