A thousand years ago, the mighty Cahokian civilization dominated the North American continent from its capital near modern St. Louis. From Wisconsin to the Gulf of Mexico, settlers and priests carried word of the power of their gods. People who wouldn't bow to that power were conquered or slaughtered. At the heart of the empire stood a vast city, teeming with tens of thousands. Power rested in one being, Morning Star, a god resurrected in the body...

"What happens when your god goes missing? The lord god of Cahokia has been spirited away to the Underworld and the empire teeters on the brink of disaster as clans fight for control. Night Shadow Star, the god's human sister, and Fire Cat, her warrior bodyguard, are the only two people who can bring him back. They descend into the Sacred Cave where monsters dwell, willing to sacrifice themselves to save their kingdom. What they find makes them question...