The episode starts when rancher, Jim Parker shoots a werewolf looking creature having just injured his son, Lyle Parker but the beast turns out to be a Native American Man.

Mulder and Scully investigate what looks like a boundary dispute but evidence suggests otherwise. They find that the rancher's cattle have all been slaughtered and when they take a look at the dead man's body it is found to have fangs, just as Jim Parker described what he saw to Mulder and Scully.

Examining the ranch, Mulder finds some intriguing tracks. Footprints which mysteriously turn into animal tracks. This convinces Mulder that this is a case of shape-shifting. While Scully is skeptical. Mulder shows her that this very region was involved in the very first X-File ordered by J.Edgar Hoover. The murders had taken place in 1946, '54, '59, '64, '78, and now '94 all supposed to have been done by viscious animals which were discovered as humans.

Meanwhile, Jim Parker is ripped to pieces on his porch and his son is discovered in a nearby field, unconscious and naked. While Mulder visits a tribal elder, Scully takes Lyle to hospital. The tribal elder tells Mulder about the legend of the 'Manitou' which is defined as an evil spirit capable of changing a man into a beast. Mulder rings the hospital while Scully has just left with Lyle and the doctor there tells him that traces of Lyle's father's blood were found in his stomach which could only have got there by ingestion. Mulder realizes that Lyle must be the new victim of the 'Manitou' so he and the sheriff race back to his ranch just intime to save Scully and shoot a bear-like beast who turns out to be Lyle Parker. Scully can't really come up with an explanation of what happened while the tribal elder leaves Mulder with the words "See you in about .... eight years" (The timespan between each murder).