D/S: Nicholas McCarthy. P: Jaime Burke, Jamie Carmichael, Ross M. Dinerstein, Sam Zuckerman. Cast: Caity Lotz, Casper Van Dien, Agnes Bruckner, Haley Hudson, Kathleen Rose Perkins, Samuel Ball, Mark Steger. UK dist (DVD): Entertainment One.

The Pact centres on a pair of sisters, Annie (Caity Lotz, of The Machine) and Nichole (Agnes Bruckner), who learn that the mother who physically abused them as children has just passed away. Nichole is ready to forgive and forget, urging Annie to come and stay with her at the family home until the funeral, but Annie’s scars run deep. Nichole moves into the mother’s empty house, a dark and forbidding property last decorated, apparently, circa 1951: all 15-watt bulbs and grubby chintz. She’s only been there one night when Horrible Things start to happen. Her Skype link to her young daughter keeps dropping out, meaning she has to pick up the laptop and wander through the gloomy house to find a better reception spot. Finally she succeeds, only to be nonplussed when the sprog brightly asks, “Mommy, who’s that lady standing behind you…?” But all that’s behind her is a dark and empty closet: a receptacle of unhappy memories, once employed by the abusive matriarch as a makeshift prison cell. Warily, Nichole moves closer to investigate…

And that’s the last we ever see of her. We now shift our attention to Annie, an angry biker chick and former druggie carting an entire chip-shop around on her shoulder. Puzzled by her sister’s failure to pick up her phone, she returns reluctantly to the family home – a place she once vowed never to set foot in again. She finds Nichole’s mobile inside the empty closet, but no sign of her sister. The babysitter shows up with Nichole’s kid, also wondering what’s happened to her; they agree to stay the night in the house until they work out what to do. Bad, bad idea.

The babysitter vanishes, after waking in the night to find a dark figure looming over her bed. Annie hears noises and gets up to investigate, but is attacked by an unseensupernatural force in the kitchen which picks her up bodily and slams her into a wall. The knife she picked up for self-defence is jammed into the wall by the impact. Hysterical, Annie picks up the kid and high-tails it out of the house for the nearest police station.

The cops are suspicious, unsurprisingly. Attending the scene they find a butcher knife embedded in a wall, and obvious signs of a struggle. Nichole and the babysitter are gone. All they have is a nerve-shredded ex-addict with a bad attitude to authority figures. But one cop (Casper Van Dien, a far cry from his clean-cut image in Starship Troopers) goes out on a limb and agrees to accompany Annie back to the house. There she heads straight for the knife in the wall and starts tearing into the plasterboard, revealing a door long-concealed behind the wallpaper. The house has a secret room, hidden for decades: inside it is an old bed-frame and lots of holes, drilled into the walls. Someone has been living there for years, silently watching the mother and her daughters. Could this discovery be linked to the unsolved serial killings of the shadowy “Judas” – and if so, was Annie’s mother implicated too…?

Gradually Annie realises that the ghostly presence in the house is one of Judas’s vengeful victims, a supernatural informant pointing her in the direction of the killer. During the sequence where Annie returns to the secret room in the dead of night, armed only with a candle and makeshift Ouija board, I believe I actually stopped breathing. The Ouija starts to spell out a word: B-E-L-O-W… There’s a trapdoor under the bed. And it’s opening…

Full credit to the filmmakers: the hidden room positively exudes evil. Writer-director Nicholas McCarthy (At the Devil’s Door) is clearly an avid student of David Lynch, especially Lost Highway and Mulholland Drive; his camera pushes slowly, slowly into inky blackness, deeper and deeper, carefully depriving us of the expected horror payoff. Anticipation builds and builds. And when suggestion has been played out as far as it will go, McCarthy only needs to give us the tiniest nudge to tip us shrieking into the abyss. Aargh. The Pact is a splendid little thriller, which should leave even seasoned horror buffs emotionally frazzled; it’s very highly recommended.