They call it the Sunstone.

As the sworn new protectors of the Hidden Citadel, Isiah struggles to fit into his new role while keeping sight of his bond with Aegon. But after a fleet of flying ships arrives on the dust storms, led by a cruel captain with dreams of conquest, Isiah and his friends are soon thrust into a deadly race against time to build a Sunstone—a devastating ancient weapon with the power to destroy cities.

Fighting to unlock the mysteries of the Ancients and delve into their long-buried ruins, Isiah embarks on a quest that will force him to come face-to-face with dangerous magical enemies and the mysterious spirit world.

Meanwhile, Lazaro returns to find Alcabaza in anarchy. With rival Raider gangs fighting over the remains of a city on the brink of collapse, their only hope to defeat the impending skyship armada lies in uniting the fractured Raiders and bringing the ancient magic of the Sunstone to light…