In a stark, chilling opening set in 1974, the Glenville Sanatorium for the mentally ill becomes the stage for a grim reunion. Dr. Annmarie McQuaid is shown around by Dr. Ryan as the film reintroduces the infamous cannibal trio from prior installments. The once-captive cannibals—One Eye [Dan Skene], Three Finger [Sean Skene], and Saw Tooth—are kept at the facility, described as having been housed there since childhood. The tension spikes when the trio manages a daring escape with a hairpin stolen from Dr. McQuaid, freeing other patients and unleashing a new wave of terror. In quick succession, the cannibals murder an orderly, a guard, Dr. Ryan, and Dr. McQuaid, setting a bleak tone for the rest of the story.
Jumping forward to present day, roughly a decade later in 2003, a lively group of nine college friends heads into the mountains for a snowbound retreat. The crew includes Kenia [Jennifer Pudavick], Sara [Tenika Davis] and Bridget [Kaitlyn Leeb], along with Lauren [Ali Tataryn], Jenna [Terra Vnesa], and Claire [Samantha Kendrick], plus their male counterparts Kyle [Victor Zinck Jr.], Vincent [Sean Skene], and Daniel [Dean Armstrong]. They plan to reach Porter's cabin, but a fierce storm diverts them and forces a detour into the same abandoned Glenville Sanatorium. The old building, long since closed, becomes a trap as the three adult cannibals hide among the ruins, mercilessly picking off trespassers. The narrative remains tight on the teenagers, while the fates of other former patients are left mostly to implication.
Inside the crumbling corridors, the group splits up to wait out the weather, and the atmosphere quickly shifts from carefree exploration to primal fear. A grim discovery jolts the survivors: Porter's mutilated body lies in a forgotten corner, a harsh omen of what awaits them. Vincent is killed by Saw Tooth, who drives a deadly metal rod through his chin and out the top of his head. The group is stunned, and dawn reveals that Vincent has vanished, prompting a frantic search.
When Kenia, Bridget, Sara, Jenna, and Claire gather in the auditorium, a terrifying trophy is produced—Porter's severed head, wrapped in his jacket. Panic erupts as the doors are locked and the cannibals—now clearly menacing figures—begin their assault from the balcony. A cruel ploy unfolds as a strip of barb-wire is tossed down and wraps around Claire’s neck, lifting her body up in a fatal twist that leaves everyone watching in horror. Kyle races to try to rescue her, but the moment passes in tragedy.
Out in the snow, the remaining survivors scatter. Lauren attempts a lone retreat to summon help, while the others barricade themselves in an office. In a tense standoff, Sara armors herself with a fire poker, and Daniel and Kyle race to gather more weapons from a storeroom filled with knives and saws—memories of a horrific previous exploration. The cannibals close in, and Daniel is captured, his screams echoing as the group discovers him being tortured and his skin sliced before being cooked in a pot of boiling oil.
With Daniel overpowered, the teens hatch a plan to trap the cannibals inside a cell. A risky choice to unleash fire is debated, but Kenia urges restraint, arguing for mercy rather than vengeance. The group works to retrieve the spark plugs they had earlier, hoping to refit their snowmobiles, while Three Finger stalks the corridors with his axe. A tense chase across the hospital ensues, culminating in a harrowing clash that ends with the trio of cannibals being corralled into a cell. The plan nearly succeeds in turning the traitors into a controlled trap, but a final twist disrupts their efforts: Kyle, whom they believed dead or captured, is revealed to be the disguise of the cannibals, and his tongue has been removed to silence him.
As the dawn lightens the snow, Kenia, Sara, and Bridget retreat to safety and attempt a last escape through a broken window. Jenna, who is behind the others, is not so lucky and is killed by a drill as she makes her way out. The remaining survivors—Kenia, Sara, and Bridget—press on through the brutal winter, pursued by the cannibals on snowmobiles. Bridget is captured but makes a desperate stand, stabbing one attacker in the arm before she is overtaken. Kenia is wounded, and Bridget is finally killed by a ruthless wheels-on-snow assault, a final, brutal reminder of the danger that stalks them.
As morning finally breaks, it becomes clear that Lauren has frozen to death only yards from a road. The chase intensifies as the cannibal force closes in on Kenia and Sara, who strike back with the momentum of sheer will. A brutal clash leaves them pursuing a last escape on a snowbound path, but tragedy follows as a barbwire trap ensnares the fleeing pair, decapitating them both just as they appear to reach a glimmer of safety.
The film closes with Three Finger returning to the scene, seizing the girls’ heads and stuffing them into the yellow tow truck that appeared in the first film. He climbs aboard with his companions, and the cannibals drive off into the endless white, leaving the survivors’ fates sealed in a chilling, snow-laden finale.
