The logline for Cody Calahan’s (Antisocial) latest feature is a tad misleading: taken at face value, it reads as though Let Her Out’s lead character Helen (Alanna LeVierge) begins hearing voices and has a split personality. That’s not entirely true – in fact, the film would be far less engaging if it were that simple.

The film finds bike courier Helen celebrating her twenty-third birthday with bestie Molly (Nina Kiri) at the fleabag motel where Helen’s sex worker mother killed herself while Helen was still in utero. Helen’s boundary and intimacy issues are disclosed in her very first scene, but we barely get a chance to dig into her issues before she is hit by a car. When she’s admitted to the hospital, Helen is diagnosed with a troubling condition: she has a strange mass growing in her head that is causing pressure on her brain and requires immediate surgery. The problem is that Helen may not last the three days until the surgery. Shortly after the accident, she begins experiencing lost time, blackouts and violent outbursts. As Helen’s aggression becomes increasingly dangerous to those around her, mysterious messages announcing her forthcoming arrival also begin to appear.

To say more is to spoil the fun, but it’s not a surprise when it is revealed that Helen isn’t entirely alone in her body and that the malevolent entity is the definition of unfriendly. Let Her Out uses Helen’s illness – a real life condition (albeit not one that manifests in this way) – as an opportunity to explore how quickly normality can descend into psychosis. Throughout most of the film, there’s a suggestion that Helen may simply be hallucinating as a result of the mass in her head, with an intriguing insinuation that part of Helen’s hysteria is directly related to her fears that she’ll turn out like her mother. Mining childhood trauma for horror is a classic trope for the genre, but unfortunately Let Her Out is less interested in exploring how her mother’s “darkness” has left her unable to deal with men and fully embrace life; that storyline putters out fairly early on.

In its place is a narrative filled with strange gender dynamics. Let Her Out opens on a distinctly unsavory note with a wordless montage of Helen’s mother half-naked with a series of johns. The men’s faces are blurred or cut off by the framing, establishing them as nondescript and, to a certain extent, immaterial (even Helen’s rapist father is treated this way). This disinterest in men carries over through the rest of the film: every man in Helen’s life is either an asshole or a pig (or both), including Helen’s handsy client Roman (Michael Lipka) and Molly’s friend Ed (Adam Christie), who hits on Helen at every opportunity. The men are loutish to the point of caricature, which immediately creates a divisive Helen vs men subtext. Initially, this is welcome because it seems as though the friendship between Helen and Molly will be the film’s foundational relationship. The girls are presented as best friends and roommates early in the film, but Molly is underdeveloped and frequently absent for long stretches rehearsing for her upcoming play. Disappointingly when Molly does reappear, her principle function is to jealously berate Helen about Ed, complain that Helen is withdrawn and, eventually, play victim and final girl to Helen’s monster.

The sidelining of its bland secondary characters does have the benefit of heightening Helen’s sense of isolation and paranoia. While Molly makes for an unsatisfactory roundabout heroine, it is principally because the majority of Let Her Out is a one-woman show that lives and dies on LeVierge’s performance. Thankfully she is more than up to the task. Helen’s transformation requires a go-for-broke physical role that demands complete dedication and LeVierge easily and convincingly sells Helen’s confusion, desperation, and fear as her life spirals out of control.

As the director and co-writer, Calahan relies too heavily on familiar techniques and conventions. Helen’s missing time in revealed in frenetic montages and music video style ellipses, which are adequate but also feel mildly uninspired, as do the transition scenes of the Toronto skyline at night. That the blackouts involve unsavory behavior (ie: Helen waking up covered in blood and dirt in odd locations) is evocative of dozens of films and television shows that employ amnesia or memory-loss as a plot device. And the less said about Roman’s malevolent painting of Helen that seemingly can’t be discarded the better (it could have been excised entirely from the plot and virtually nothing would have been lost).

More successful are two stand-out scenes that occur late in the film. The first is set in an abandoned subway station when Helen finally succumbs to her dark desires following a sexualized attack. As an operatic chorus plays on the soundtrack, the camera does a slow 360 pan away from a graphic act of violence involving a head and a box cutter, leaving only the sound, soundtrack and our imagination to fill in the blanks. The other memorable scene is the climax when Molly confronts Helen in the motel room where her mother committed suicide. Here the film’s dedication to body horror, practical visual effects, and LeVierge’s performance merge to create a gooey, disgusting and thoroughly enjoyable reveal that any self-respecting horror fan will applaud.

Ultimately Let Her Out is let down slightly by a run of the mill script, some uninspired technical decisions and a host of bland secondary characters, but it is worth a look for its paranoid tone and Alanna LeVierge’s show-stopping, go-for-broke lead performance.

Let Her Out screened at the Toronto After Dark Film Festival.