In 1936, a German professor, Richard Wirth, is hosted by the Wollners, a family of German emigrants in West Virginia. The Wollners believe him to be a visiting scholar, but Wirth turns out to be a Nazi occultist who seeks a Viking runestone buried on their property. When Wirth reveals he wants to use it for evil, he is interrupted by the family, who trap him in their basement and bind him through a ritual that requires frequent human sacrifices. Linked to Wirth, the family survive through the decades, operating as both captors and servants to Wirth, who they keep weakened.
In 2007, 25-year-old Evan Marshall is surprised when his older brother Victor suddenly appears after having disappeared during a camping trip in rural West Virginia. Victor explains that he has escaped his captors, and they quickly prepare to return for vengeance. The brothers head to the farm and confront the Wollners. They, in turn, warn the siblings about Wirth. They do not listen until Wirth gets out of the cellar and begins his terror. Wirth reveals that the reason Victor was able to escape was because Wirth knew that Victor would come back to the farm for revenge and would eventually free him from the Wollners, so he let Victor go on purpose. The brothers manage to poison and decapitate Wirth, but as a result the Wollners rapidly turn old and die. Before the youngest dies, she tells Evan that SS leader Heinrich Himmler has sent eight more Nazi agents to different farms. Evan finds a map that was under the farm and discovers that others like Wirth are at other farms. While Victor returns home to his family, Evan heads out to the other farms to stop the Nazis.