In the small New Mexico town of Furnace Flats (population: maybe six), Pete Jensen, an elderly recluse, dies suddenly. When his nephew, Nick Richards, comes to town to settle the old man's affairs, people start turning up dead or maimed. As fate would have it, Pete Jensen and Nick Richards are the same person. Jensen sold his soul to the Devil for restored youth and vitality, along with the power to shapeshift into any living creature.

The film offers no explanation as to why Nick is killing these people. Maybe he's avenging perceived wrongs they did to Pete Jensen. Maybe Nick hopes to steal the town's only woman from her fiance. Maybe Nick is just plain evil, having sold his soul to the Devil. But there's no way of knowing because we're offered no clues. Another plot hole occurs when the sheriff tells Nick that Pete Jensen appears to have died violently. The sub-plot goes nowhere. At Nick's house, the sheriff's dog digs up what looks like a human bone. Again, the matter is not pursued. Toward the end, Nick tries to kill David, the man for whose maiming he was previously responsible. The film doesn't even try to explain why Nick didn't simply kill David to begin with instead of maiming him.

There's also the usual sub-par acting, in particular Spencer Carlisle as the sheriff (who is all too quick to buy into an occult explanation for the carnage). Finally, as with many B-movies of this era, it's too dramatically slack for its running time. Too little happens in these 73 minutes, resulting in long stretches of tediousness.

However, the film has its moments. Among them:
- Pete slaughters a goat (depicted in shadow) and uses its blood to write out his pact with the Devil;
- the town doctor (Edgar Buchanan) points out that Nick's not sweating in the 100-degree heat;

- David's german shepherd (under Nick's power) goes berserk and attacks its owner;
- Nick brings the town drunk to his house to witness him shapeshifting back into Pete Jensen. When the drunk flees in terror, Nick/Pete becomes a horse and stomps him to death. It makes no sense, but it sure is memorable.
Item: The opening credits read, “Introducing Ed Nelson as Pete Jensen/Nick Richards.” By 1961, Ed Nelson had been doing TV and movies for a decade.

Item: Nick dies when the sheriff shoots him. Looks like his pact with the Devil did not include invincibility.
Item: Several cast members went on to TV success. Ed Nelson was in “Peyton Place,” Edgar Buchanan (as the town doctor) played Uncle Joe in “Petticoat Junction,” and Jean Allison (the female lead) did episodic TV for 20+ years.