Keys to the Demon Prison by Brandon Mull

Description

After centuries of plotting, the Sphinx—leader of the Society of the Evening Star—is after the final artifacts needed to open the great demon prison, Zzyxx. If the legendary prison is opened, a tide of evil is certain to usurp control of the world.

In an effort to intercept the final artifacts, Kendra, Seth and the Knights of the Dawn race to strange and exotic preserves across the globe. The stakes have never been higher. The risks have never been more deadly.

In this explosive series finale, allegiances will be confirmed and secrets revealed as the forces of light and darkness collide in a desperate, climactic battle to control the keys to the demon prison.