Sheol — Jason Brant

Sheol is the third and final book in the West of Hell trilogy.
After escaping the decimated town of Gehenna and the mighty Tartarus river, Karen finds herself trapped in a prison in the city of Sheol. Knowing that an army of the dead is marching across the desert behind her, Karen must find a way to escape the sadistic Evans, and rally the citizens of Sheol for one last stand against an enemy of biblical proportions.