Halle Berry in Alexandre Aja Horror

Splat Pack veteran Alexandre Aja tries his hand at a family-in-peril horror film in the style of Quiet place Franchise with Never let go. But above all, the French director manages to make us overlook his entertaining, trashy forays into B-movie trash, with monster movies revolving around voraciously biting, flesh-eating fish (Piranha 3D) or giant Florida alligators disturbed by a hurricane and flood (Creep). Whatever their strengths and weaknesses, these films were fun popcorn entertainment with a punch. Fun is nowhere to be found in Aja's latest, which starts off mildly intriguing and offers a few refreshing moments of shock before running out of steam.

Part of the problem with KC Coughlin and Ryan Grassby's weak script is the laboriousness of its structure. Halle Berry plays a woman, initially identified only as Momma, who lives in the isolation of an old wooden family home with her fraternal twin sons, Samuel (Anthony B. Jenkins) and Nolan (Percy Daggs IV), who are not yet even teenagers. Whenever they leave the house in search of food, they must remain tied to its foundation with thick ropes and: Never. Let. Go. That way, evil can't touch them and make them do bad things, Momma explains, so often that you just want to scream, “Jesus Christ, we got it!”

This amorphous evil has apparently so poisoned humanity that civilization is at an end, and only the warmth and love of a house the boys' grandfather built as a haven for his anxious wife can protect them. We get a dose of this initial situation from Nolan offscreen, and then a lot more from Momma in ominous stories and warnings at dinner that are both patiently caring and angry. There's even a rhyming spell they recite before venturing out, and another once they're back inside and their hands touch the sacred wood. The premise is burdened with a lot of convoluted lore that somehow never makes it more coherent.

Evil can take many forms, from the snake that crawls around the moss-covered tree roots of the forest to zombified humans waiting for one of them to break free. These demons want to destroy the love in the boys, Mama tells them. It can get into their heads and tear them apart, causing them to kill each other.

One manifestation of evil that seems particularly interested in Momma is a hillbilly in a housedress (Kathryn Kirkpatrick) who drools ink and has a tongue like a lizard – or like Gene Simmons in his Kiss heyday. Suspicions arise early on that she was once part of the family. The boys' deceased father (William Catlett) also circles the house at night while Momma sits in a rocking chair on the porch sharpening her hunting knife. Aside from the huge bullet hole in his back, he still looks alive.

Momma is so angry after a near-miss caused by the boys' recklessness that she threatens them at knifepoint and makes them repeat the rhyme for the 800th time. She also has a sort of purification ritual where she locks one of them at a time in the basement so they can imagine the darkness taking over their world and then force themselves to return to the light.

The film has already started to fall apart at this point due to the ambiguity and repetition of the plot, so it is a welcome shot of craziness when Berry threatens to Carrie. Unfortunately, she falls short of that hellfire hysteria (at least for now), sticking with an underlying witchy intensity and a fear that consumes Momma's every waking moment. Still, a seed is planted that suggests her maternal devotion may be more twisted than it seems.

A harsh winter has wiped out everything edible in their greenhouse, along with most of the natural vegetation worth eating, and forest animals are slow to return, putting the family at ever-increasing risk of starvation. A scrawny squirrel that Mama skinned and roasted seems to be their last real food before they're reduced to sautéed tree bark.

Hunger, fear and desperation drive a wedge between the brothers as Nolan begins to doubt his mother's dire warnings and plans to go in search of food without a rope. Since Mama is the only one who sees evil, they have always had to believe her. But Samuel believes her unconditionally and begs Nolan not to put them all in danger.

In his latest film, the claustrophobic Netflix sci-fi survival thriller oxygenAja chose a setup that couldn't have been tighter, keeping the scenario tight and the tension going. He works on a larger canvas with Never let goa Southern Gothic chamber piece with three characters. But the film gets weaker and weaker once we've digested all the lessons from Momma.

The friction between the brothers is well portrayed by the two great young actors – Jenkins has taken on more than his fair share of evil of late, following Lee Daniels' unintentionally cheesy outburst of possession, The Redemption – and the makeup team does a great job on all three leads, hollowing out their eyes and cheeks as malnutrition takes its toll. But the film can only get so much out of Is Mom Crazy or Is She Telling the Truth? before it becomes monotonous.

A surprising development about halfway through ratchets up the tension considerably, and a passing hiker (Matthew Kevin Anderson) further reassures Nolan that normal life goes on out there, beyond the forest boundaries of their dark fairy-tale world. By this point, however, the film has become an inevitable “And then there was one” countdown. Even though Aja fuels the final section with plenty of fiery action, shifting perspectives, demonic apparitions, and a touch of body horror, the film is dull and silly, not scary.

On a craft level Never let go is sophisticated. Aja's longtime cinematographer Maxime Alexandre uses wide shots to place the characters in a grim natural setting, full of mystery and threat. The forest (filming took place outside Vancouver, which stands for rural Tennessee) is dense and atmospheric, its primal sounds and the voices of mostly unseen animals blending effectively with a robust, eerie score by French indie-pop artist Robin Coudert, who records and composes for film under the name ROB.

Production designer Jeremy Stanbridge makes the house a separate entity, full of secrets and lit only by candles and oil lamps. As a reward on new moon nights, Momma winds up the old-fashioned gramophone and has the boys sing and dance to the late 1920s country-folk song “The Big Rock Candy Mountain,” which hints at the place's long history.

Berry, who is also a producer through her company HalleHolly, does her best. De-glamorous almost to the point of wildness, slipping in and out of a Southern accent, she deftly blurs the lines between fierce protectiveness and paranoid and wacky personality for much of the time. But all her conviction can't add substance to a story that's far more complicated than it is complex, and a film that takes itself far more seriously than the material deserves.