Five Oregon college students set off to find out what happened to the nine hikers who mysteriously died in the Dyatlov Pass incident.
In Russia, the students first try to contact a member of the initial 1959 expedition who turned back after becoming ill on the first day.
In an upstairs window, the students see a man they assume to be the survivor; he holds up a sign in Russian and is dragged away by orderlies.
Jensen reveals that as a teenager he had heard the howling during a bad acid trip that ended with him being arrested while yelling incoherently about demons.
Holly attempts to comfort Jensen by relating that she has had recurring dreams about Dyatlov Pass, which she interprets as fate.
After they fire a flare, Russian soldiers posing as a rescue party arrive, kill Andy, and chase the three survivors to the bunker.
The mutants kill J.P. and chase Jensen and Holly into a sealed room with a strange-looking tunnel that leads further into a natural cave.
Unwilling to starve to death or face the mutants, Jensen and Holly choose to step into the wormhole.
[10] Miriam Bale of The New York Times called the film "an upgraded Blair Witch Project that is hilarious, though it is not clear whether this is intentional or not.
[14] Philip French of The Guardian wrote that it "adds nothing to a real-life mystery from the Soviet era" and that the explanation is too outlandish.
[16] Gareth Jones of Dread Central rated it 3.5/5 stars and called it "a thoroughly intriguing mash-up of sci-fi, horror and real-life mystery.
"[17] Matt Glasby of Total Film rated it 3/5 stars and called it a cheesy midnight movie that requires a forgiving audience.
[20] Scott Weinberg of Fearnet called it a "simple but crafty little horror tale" with a payoff that can "come off as ridiculous or novel".
[21] Chris Holt of Starburst rated it 7/10 stars and wrote that it is "a fascinating and gripping film that despite being fundamentally flawed, is well worth your time.