Spoiler Alert: OK, not a true spoiler–this book is too complex to have a simple ending that can be “given away.” Still, the review may tell you more than you want to know. No big deal. Read it anyway.

Anyone who has used a fitness tracker or biometric watch knows that the data these devices generate can have the unpleasant side effect of alienating you from your own body, transforming it from an integral part of your overall “self” into what feels like an external object with quantifiable outputs.  What’s so clever about Hildur Knútsdóttir’s novel The Night Guest (2024) is that it takes this disconcerting and distinctly modern experience, which we articulate in a figurative way, and makes it literal through the classic horror trope of the doppelganger: it isn’t “as if” the book’s protagonist Iðunn is disconnected from her body; she actually is (or so it seems–there’s some ambiguity there). The novel’s thematic preoccupation with doubleness is cleverly mirrored (ha ha!) in its style and structure, with its single sentence chapters and truncated narrative voice indicating the presence of an inaccessible and unknowable other. While I was completely on board with the first three-quarters of The Night Guest, I was underwhelmed by the ending which uses the tired Freudian concept of repression to account for Iðunn’s sleepwalking. Still, if Knútsdóttir’s reliance on a psychoanalytic model seems stale, the way that she leverages our inchoate fears surrounding health tracking technologies will resonate with anyone who has ever counted calories or steps–which, at this point, is pretty much everyone.

The Night Guest is a little bit like Dr. Jekyll and Mr. Hyde if the eponymous doctor had possessed a Fitbit. Iðunn, a young Icelandic woman, has been suffering from extreme fatigue which her doctor can’t explain. Hoping that more exercise will increase her energy levels, she purchases a pedometer to measure her physical activity. One night, she forgets to remove the device before going to bed and, in the morning, it indicates that she has taken 47,325 steps when she was supposed to be asleep. Every day she has new bruises, and sometimes there’s blood under her fingernails. Where has she been going and why? 

Early in the novel, Iðunn has a deep suspicion of tracking technologies, and she locates the danger where we all do–in outsiders, either individuals or agencies, who may gather the information for nefarious purposes. Worried that her national identification number might be exploited by political parties, she’s reluctant to associate it with an online account. And her new pedometer, she fears, could be “spyware” that poses a threat to her “personal security”: “All the data these devices collect. And who knows who’s sitting at the other end watching” (14). But what about when the person watching at the other end is you? Knútsdóttir suggests that, while concerns about hackers and government bureaucrats are legitimate and widely shared, the real risk lies not so much in others monitoring us as in us monitoring ourselves. A cheery retail associate unwittingly hints at these perils when he outlines the creepy ways in which Iðunn’s pedometer will change how she relates to her body. “You can send data,” he enthuses, “automatically to a computer. Put it in a graph or display it any way you want. Or automatically post your stats straight to Facebook” (14). In other words, this gadget will allow Iðunn to reduce her unified experience of selfhood into a series of abstract units, which she can then analyse, manipulate, and even make public. 

This all sounds vaguely menacing but, really, what’s the harm in evaluating your own movements and behaviors? The harm in it, at least in the world of horror fiction, is that, through all of these assessments, you might realize the truth of your worst fears: Maybe your body really does have a separate existence–one that’s governed by a consciousness bent on destroying the life you’ve built. While Iðunn’s pedometer doesn’t create this separate self–it merely captures something that already seems to exist–the centrality of a health tracking technology to the story gestures toward our anxieties about how these devices may warp our self perceptions. Knútsdóttir heightens our inarticulable fears about losing touch with our bodies by giving these vague imaginings a concrete and exaggerated form.

While phone cameras and biometric watches are relatively new, the fears of self-alienation that they raise are very old, and Knútsdóttir explores them through the traditional trope of the doppelganger, that uncanny double described by Freud in Das Unheimliche (1919). When Iðunn meets Már, the former lover of her dead older sister Ingrunn, she can feel him correlating their features, mapping Ingrunn’s eyes, nose, and mouth onto her own. She’s almost identical to her sister, but the likeness is nonetheless slightly off, and Már stares at her, stunned by the dissonance between the familiar and the unfamiliar, the homely (heimlich) and the unhomely (unheimlich), which, according to Freud, defines the experience of the uncanny (unheimliche). Iðunn feels it, too–though not, it seems to me, as much as she should–when her image in the mirror doesn’t reflect what she’s doing, remaining stone faced while she smiles and vice versa. But Knútsdóttir deploys the doppelganger trope to greatest effect when Iðunn watches a video of her sleepwalking self, and the recorded figure, who seems to be fully conscious, smirks maliciously at the camera. In a moment that captures the intense surrealist horror of the body double, Iðunn disavows the person in the video, telling herself–despite the impossibility of it–that it must be someone else. Through this constant play between similarity and difference, self and not self, Knútsdóttir gives the novel a disorienting quality that adds an eerie depth to her sparing prose, a minimalist style that’s instrumental in her portrayal of duality. 

Indeed, the extreme leanness of Iðunn’s voice points toward an internal psychological fissure that is just as frightening as any external enemy. The first person narrative mode is a great way to explore interiority because a protagonist’s present thoughts, much like those of real people, will almost inevitably connect to their anxieties, past experiences, and hopes for the future. What’s unusual about Iðunn’s perspective is that it is markedly restricted. For instance, we have almost no insight into her relationship with Ingrunn, and the few details we do have suggest that their dynamic was of the typical big sister/little sister variety, characterized by the usual mix of adoration, jealousy, and petty cruelty. So why would Ingrunn return from the dead to murder cats and crush her younger sibling? Clearly there is something that Iðunn’s isn’t telling us about their shared history. And about so many other things. Despite the first person POV, we have limited access to her consciousness–and so, it seems, does she. It’s as if a curtain were blocking her–and, by extension, us–from parts of her own mind which, for reasons unknown, are off limits. 

These forbidden zones are given material form by the novel’s numerous (nearly) empty chapters. Made up of single sentences like “What is out at Grandi?” or “I’m afraid to call him,”  these terse sections underscore the fact that information is being withheld. If Iðunn’s thoughts were weblike, expanding as most people’s do in endless chains of association, it would be natural enough for her to elaborate on her ties to the Grandi waterfront district (didn’t her sister drown in a harbor?) or to expand upon her fears for Már (what does she suspect has happened to him?) But, instead, her mind–at least according to the page–is vacant, and it’s in these absences that we sense the presence of another intelligence hidden within her, one that knows what she doesn’t and that could fill in the gaps. In Knútsdóttir’s hands, negative space becomes content; her strategically placed lacunae symbolize and create room in the text for a separate consciousness that’s in abeyance when Iðunn is awake.

This mysterious entity could be so many things–personally, I was hoping for some kind of alien influence–but the book isn’t subtle in its preference for a Freudian reading. 

I’ve used “doppelganger” and “uncanny” to discuss the ways in which a perceptual conflict between the familiar and unfamiliar can create a sense of unease–that’s how most people use these terms nowadays. But while this tension is important to Freud, for him, the deeper significance of these concepts (no pun intended) has to do with repression: A doppelganger is the manifestation of unacknowledged anxieties, desires, and conflicts in a seemingly external body. If you see one, it means that elements of your unconscious mind are breaking through to consciousness in a circuitous way, assuming the form of an outsider. Unfortunately, it’s this aspect of the doppelganger on which Knútsdóttir relies the most.

The Night Guest abounds with metaphors for Freud’s two part version of the self and for the tenuous barrier–always on the verge of being breached–that keeps them separate. The most obvious–and, for an American reader, interesting–example of this is the turf house with its flexible yet fragile animal-hyde windows, an image that Iðunn returns to again and again: “The dark tries to force its way into my consciousness, like some monster lying in wait beyond the translucent stretched-skin windows of a turf house. Half-buried and isolated, I feel the thin membrane that separates me from the darkness distend–but it doesn’t rupture” (52). She also looks to the night sky for language to convey her impression of a rapidly destabilizing self, describing “the dark between the stars” as a negative force which “presses against my shields” until they “are about to collapse” (81). With these barely metaphorical metaphors, she practically abandons figurative interpretations of her experience in favor of an almost clinical exegesis (107-108). The effect of Iðunn’s movement toward an explicit and weirdly professional account of psychological processes, complete with turns of phrase that Freud himself may have used, is that, despite the book’s heroic attempts at maintaining ambiguity, it’s too obvious that no genuinely external entity–neither her sister nor any other foreign presence–is responsible for what’s happening to her. I held out hope that her repeated references to cosmic darkness were foreshadowing a Lovecraftian twist–a direction that would feel original in a story about a sleepwalking Icelandic woman–but instead it ultimately follows the predictable path offered by old-school psychology. And that’s disappointing because, from Psycho to Black Swan and beyond, it feels like repression is the answer to almost every horror mystery. 

While the ending of The Night Guest doesn’t fulfill the promise of its intriguing premise, the novel is still worth reading for its smart stylistic choices and innovative treatment of health-tracking technologies. To me, these devices could drive at least a dozen different horror plots but, so far as I know, Knútsdóttir is the first to tap into their potential.