Possession has always been a tried and true formula in the horror genre. It’s one of those subgenres that are so worn down you wonder if the well isn’t completely dry. Even the most successful examples, films like The Conjuring, lean heavily on what came before them. Which is what makes You Shall Not Sleep a genuine breath of fresh air. Gustavo Hernández has made a solid horror film, providing one of the freshest takes on possession I’ve seen in a long time.

Hernández is best known for his 2010 thriller The Silent House, a gritty, low budget horror film designed to appear as one continuous shot. You Shall Not Sleep feels an order of magnitude larger. Eve De Dominici stars as Bianca, a young actress struggling to juggle her career with caring for her mentally ill father. Everything changes when Bianca gets the opportunity of the lifetime to audition for a role in the new play from the legendary avant-garde director Alma Böhm (Belén Rueda). Bianca and another actress, Cecilia (Natalia de Molina) will compete for the role based on a real-life killer, who murdered her husband and burned her house to the ground. But, like all of Alma’s projects, there’s a twist.

The setting is an abandoned mental institution, brought to beautifully horrid life by Guillermo Nieto’s cinematography. Here the actors prepare for a one-night-only show, rehearsing and following one simple rule – don’t fall asleep. Alma prohibits the actors from sleeping, believing that sleep deprivation will bring them closer to their characters. But as Bianca and the other actors keep themselves awake for days, the line between what’s real and what isn’t becomes blurred. But what if staying awake is more dangerous than they thought? What if, by not sleeping, they are leaving their minds open to intruders?

You Shall Not Sleep is successful, not because it’s wholly original, but because it borrows superbly. It blends some of the best elements from Nightmare on Elm Street and The Conjuring with a sensibility that feels inspired by the supernatural gallon films of the 1970s and 80s. The film takes place in the 1980s, but it feels less like a period piece than a story separated from time. Hernández imbues the frame with a dreamlike quality, making the whole film feel like a macabre gothic bedtime story.

The success of You Shall Not Sleep is predicated on twisting the audience’s perception of what is real and what isn’t. We’ve seen narrative elements like this before a number of horror films, particularly in the Elm Street films, but by setting the film on a stage, screenwriter Juma Fodde adds another layer of deception. Are these people simply sleep deprived, are they acting, or is something more insidious going on? Fodde weaves an intriguingly twisted yarn that culminates in a satisfyingly fiery ending. The film can’t quite help itself from including on last little sting, but it eschews franchise building potential in the spirit of telling a good scary story. And that’s what the genre really needs – not more series, not more spin offs – just good old fashioned scary stories.

Verdict: 4 out of 5

Gustavo Hernández has made just three films in the last eight years, which means we might need to wait a while to see his follow up, which is a shame, since You Shall Not Sleep feels like a big step forward. It’s a taught, well-conceived thriller that confirms Hernández as one of the best working in the genre today. Fans of psychological horror should flock to see this. You Shall Not Sleep is having its international premiere at the 2018 Tribeca Film Festival.