A couple heads into the quiet expanses of the Scottish Highlands for a camping trip, where a simple gift—silver letter opener—becomes a chilling omen. Shortly after, their tent is breached by unseen assailants, leaving the scene shrouded in mystery and menace. Meanwhile, through a dense, misty forest in North Wales, a soldier named Cooper, Kevin McKidd, races to outrun his pursuers. He fights back, but is overpowered and subdued. It’s revealed that Cooper is seeking to join a special forces unit, yet his stubborn refusal to blindly follow orders leads to a confrontation with Captain Richard Ryan, Liam Cunningham, who tries to force him to shoot a dog in cold blood. Cooper resists, and the moment of defiance costs him dearly as he’s sent back to his unit.
Four weeks pass, and a six-man British squad, including Cooper, is dropped by helicopter into a remote district of the Scottish Highlands for a training exercise meant to mimic a real clash with a Special Air Service (SAS) unit. Dawn finds them moving through rough terrain, and by daybreak they discover the SAS unit has been savagely slaughtered. The lone survivor, a badly wounded Captain Ryan, speaks in cryptic terms about what attacked them, hinting at a threat that defies ordinary explanation. As fear grows, unseen pursuers close in, forcing the soldiers to retreat.
In the escape, Corporal Bruce—Thomas Lockyer—is felled by a brutal impalement from a snapped tree, a grisly marker of the night’s onslaught. Sergeant Wells—Sean Pertwee—suffers a violent assault but is rescued by Cooper and carried to a roadside where Megan, a zoologist Emma Cleasby, arrives in a vehicle to ferry the group to safety at an isolated house belonging to a local family. The remaining soldiers—Wells, Cooper, Spoon, Joe, and Terry—huddle inside as darkness gathers.
As the full moon rises, the house is ringed by attackers who reveal themselves to be werewolves. The group fights to reach a battered Land Rover, only to discover it wrecked by their attackers. With ammunition dwindling, they stage a desperate defense, clinging to a glimmer of hope that sunrise will reverse the creatures into their human forms.
Cooper and Wells tend to Wells’s wounds, while the tense siege continues. Terry Milburn—Leslie Simpson—is abducted, leaving the others more exposed and desperate. Spoon—Darren Morfitt—creates a diversion, and Joe Kirkley—Chris Robson—steals a Land Rover to mount a last-ditch assault on the house, only to be killed by a werewolf lurking in the back seat.
Interrogation reveals a shocking truth: Captain Ryan was ordered on a government mission to capture a live werewolf for study and potential weaponization, and Cooper’s squad was bait—deemed expendable. Enraged, Wells and Cooper rush to kill Ryan, but the captain transforms into a werewolf and escapes into the forest. It’s disclosed that the Uath family, owners of the house, are werewolves.
With the Land Rover and petrol, the soldiers rig a bomb to blow the barn where Megan claimed the werewolves supposedly hid. Yet Megan shocks them by admitting there were no werewolves in the barn; she is a werewolf herself and a member of the Uath family, and she had unlocked the back door to let others in. Wells shoots her in the head just as she begins to transform, buying a critical window for escape. Wells and Cooper race upstairs, while Spoon fights a werewolf in the kitchen. The first werewolf is bested, but a second one overpowers Spoon, killing him as he fights to survive.
Wells and Cooper leap through the floor into the kitchen, only to discover Spoon’s remains. As Spoon’s body begins to turn, Wells directs Cooper to shelter in the cellar where the bodies of previous victims lie. Wells hands Cooper a roll of film from a flash camera used to stun the werewolves, a final proof of what unfolded. The werewolves smash into the kitchen, confronting Wells as he cuts a gas line and blows up the house, sacrificing himself to extinguish the threat.
With sunrise approaching, Cooper tries to leave, but the lingering werewolf threat—Ryan—appears. In a brutal confrontation, Cooper drives a silver letter opener into Ryan’s chest and then shoots him in the head, ending the immediate danger. Cooper, accompanied by Megan’s Border Collie Sam, Villrikkes-Acer, crawls out of the cellar to safety.
Back in the world of headlines, Cooper’s story—titled > Werewolves ate my platoon! —and the accompanying photographs run in a sensationalist tabloid, cataloging the collapse of the mission and the brutal truth behind it, alongside the football match results of England vs. Germany. The film closes on a stark, unsettling note: a small band of soldiers surviving a night of terror, the world left to wonder what truly lurks in the dark and what governments are willing to do to harness fear itself.
