Father John, a former Army Ranger, is a legend in the Catholic Church for having conducted over 90,000 successful exorcisms of not only people, but also of houses. The story begins, as a 20-something nun, Sister Sarah, accompanies Father John on the exorcism of a young woman. While the exorcism is underway, in Alaska, Josh, a 30-something hunter and Native American, has encountered an enraged Bigfoot, who has just killed one of his friends and smashed the legs of another friend. After the successful exorcism, Father John receives notification that he's to fly to an Alaskan island, in order to conduct a very unusual exorcism: An exorcism of Bigfoot.