A summoning gone awry leads to problems for Penelope, who is driven from her home by phantom parties, a dancing stove and a wave of demonic force that tosses her around like a ragdoll. Looking for help, she turns to her friend Robbie, who brings her to David Rountree, a Lakota shaman. Robbie and David embark on a whirlwind journey of learning, racing against time, visiting sites of spiritual power and acquiring artifacts and allies in their quest to exorcise the evil before it can seriously injure someone - or worse. David and Robbie's mission to banish the demon culminates in an astonishing psychic battle on Halloween night.