Praised by Bong Joon-ho as “one of the most surprising and smart screenplays I’ve read in the last ten years… the final film is also one of the most shocking debut features in the last decade,” Jason Yu’s Sleep challenges conventional horror rules to create a restrained, deeply moving film where fears are rooted in reality. The film presents an unsettling portrait of a marriage unravelling under the strain of a sleep disorder, turning a shared bed into a tragic purgatory. Anchored by the powerful performances of Jung Yu-mi and Lee Sun-kyun, Sleep follows Soo-jin and Hyun-su, a couple facing increasingly disturbing behaviour stemming from Hyun-su’s unusual condition.
What makes Sleep so compelling is how it plays with familiar domestic anxieties while amplifying them through the lens of horror. Yu’s fascination with real-life sleep disorders played a significant role in shaping the story.
“I think everyone has come across shocking or terrifying sleepwalking stories, whether on the internet or in the news—someone jumping off a building while asleep, driving while sleeping, or even harming someone by their bedside,” Yu tells The Asian Cut. “I remember feeling incredibly shocked by these stories and wondering what the everyday lives of such people must be like—I couldn’t even fathom it. But more importantly, I thought about what the lives of their loved ones, who have to be by their side every day, might look like.”
This interest in the devastating effects of sleep disorders extends beyond the individual suffering and into the family dynamics that are impacted, which is at the heart of Sleep‘s psychological horror. The film masterfully sidesteps traditional horror tropes like jump scares, choosing instead to explore the slow erosion of trust between a couple caught between love, fear, and a haunting they can’t escape.
“I love jump scares in horror films when I’m watching them, but I didn’t think Sleep was that sort of film,” Yu elaborates. “There’s no evil presence or ghost—everything happens in this boxy, square room, just [Soo-jin] and [her] husband. There was very little reason to have jump scares.”
Yu’s decision to focus on the claustrophobia of the couple’s small home, where the apartment itself becomes both a sanctuary and a prison, enhances the psychological horror of Sleep. His use of tight camera shots and the confined setting builds a tense, intimate atmosphere where trust between Soo-jin and Hyun-su frays, slowly but surely, as the terror mounts.
The tension in Sleep is not just about the fear of what Hyun-su might do in his sleep but also the creeping realization that Soo-jin, his wife, may never be capable of fully understanding him. This growing disconnect mirrors how mental health can fracture a marriage, and in Sleep, this theme is at the forefront, intertwined with the themes of trust and fear between the couple.
When asked about how deeply these themes resonated with the cast and crew during production, Yu notes, “Most of the themes were established during the screenwriting phase, but I was always concerned, being a debuting director, whether I would be able to reflect that on the screen. It’s all explicitly spelled out in the screenplay, but you can’t just copy and paste that onto the screen.”
“You have to have great performances, cinematography, and production design—everybody has to be on the same page. I was more relieved, less surprised, that they were able to convey what was on the page. I’m very grateful for them. They were all excellent in their field—top cast and top crew,” he adds.
While Sleep is his debut feature, Yu’s path to making the film is grounded in rich cinematic experience. Having worked as an assistant director under Bong Joon-ho on Okja and for Love Lee on Real, Yu absorbed the meticulous character-driven approach of Bong and the visual boldness of Lee. But with Sleep, he found his voice, crafting a film that trades overt scares for psychological tension.
Reflecting on the lessons learned during its making, Yu shares that, “Every actor has their own way of approaching the craft, and as a director, you have to be sensitive to their approaches and direct them individually. You can’t force one style on everyone.”
He continues, “It’s funny because Sleep only has two main characters, but their acting styles were drastically different, which taught me a lot. I also learned the importance of staying calm when things go wrong on set. There’s the cliché: keep calm and carry on. There are always obstacles—whether it’s the sun setting too quickly or a prop not working. Lee Sun-kyun, who played Hyun-su, emphasized how critical it is to stay calm and keep making decisions within your given situation.”
In many ways, Sleep is a study in contrasts. Soo-jin is portrayed as the more emotionally volatile partner, with sudden bursts of anger and fear, while Hyun-su remains more passive, even as his body becomes a vessel for something terrifying. The dynamic raises questions about responsibility within their marriage, considering Asian cinema’s frequent focus on family dynamics.
“Sleep reflects a current shift in how people, especially in Korea, view marriage. Where marriage used to be about endurance and sacrifice, there’s more focus now on individual happiness. I wanted more from marriage myself while writing Sleep—something romantic and enduring,” Yu explains. “You see this contrast between the younger couple and older characters in the film, where [mature figures] have a more modern view on marriage, but Soo-jin and Hyun-su seem to cling to traditional ideas of responsibility and sacrifice.”
Yu reveals that his personal life significantly impacted his perspective on marriage as he was preparing to marry his long-time partner while writing the screenplay. This personal experience shaped the film’s portrayal of Soo-jin and Hyun-su’s relationship, making Sleep not just a horror story but a reflection of the evolving expectations around marriage: “I wanted the bond of marriage to be strong. Sometimes it requires sacrifice, as you see in the film, and that’s a more traditional view that’s currently being deviated from,” Yu says.
The filmmaker accomplishes this with outstanding performances by Jung and Lee, whose nuanced portrayals of a couple struggling to stay connected elevate Sleep beyond its genre. Their chemistry brings authenticity to the film’s emotional core, making the tension between love and fear all the more palpable.
Sleep is far more than a conventional horror film—it’s a deeply personal exploration of marriage, mental health, and the slow unravelling of trust between two people caught in circumstances beyond their control. By grounding the film in real-life anxieties like sleep disorders and contrasting modern and traditional views of marriage, Jason Yu crafts a haunting meditation on love, sacrifice, and the things that can’t always be fixed, no matter how hard we try.
As a first feature, Sleep not only showcases Yu’s unique directorial voice but also signals the arrival of a filmmaker willing to challenge conventions in genre and storytelling. With lessons learned from the making of Sleep, it’s clear that Jason Yu is a director to watch, and whatever comes next, it’s bound to leave a lasting impression—just like his first.
