There’s a moment near the end of the first act of Irish horror film Sea Fever that makes it clear to audiences just what type of film it is. Strange colored barnacles have begun appearing on the lower deck of fishing vessel Niamh Cinn Oir, creating unusual circles that have altered the boat’s physical texture. These circles have a gooey, mushy consistency to them – a gentle probe of the finger can push right through, which is exactly what a character does, despite the uncertainty of what lies beyond.

One of the thrills of watching horror films is waiting for the scare(s) to come. In this instance, writer/director Neasa Hardiman is well aware of those expectations: she keeps the camera trained on the hand and the strange circle, the music crescendos and… nothing. Hardiman resists the easy impulse to rip off an appendage in the most satisfying denial of expectations possible. Because that’s what Sea Fever is: a subversion of conventions, a zig when other (more conventional) films would zag and, above all, a smart film.

Sea Fever tells the story of smart, blunt, introverted grad student Siobhán (Hermione Corfield). Early in the film she is ordered out of the lab and into the real world by her professor. Siobhán specializes in behavioural patterns and her responsibilities aboard the trawler are to photograph and analyze their catch for abnormalities. Unfortunately for her, the crew are proper sea farers, which means that they are both extremely pragmatic and superstitious, particularly in regards to her red hair (which is bad luck on a boat).

Trouble looms when Captain Jarrod (Dougray Scott) discovers that the area he had planned to scour for fish is part of an exclusion zone. Unbeknownst to his wife Freya (Connie Nielsen) and the rest of the crew, he silently takes them in anyways – the crew is in a compromised position financially and they need a payday.

Almost immediately the ship becomes caught in…something. Shortly thereafter the mysterious barnacles appear and a cursory (terrifying) underwater investigation by Siobhán suggests they have been ensnared by a giant luminescent creature lurking deep below the surface. A mysterious boat on the horizon and a sick crew member soon raise the stakes as the crew must decide what they are willing to do – and sacrifice – in order to get home alive.

To casual viewers the description likely sounds familiar, evoking a variety of water-based horror films such as Leviathan, Sphere, The Abyss and even Virus. And yet Hardiman regularly seeks out ways to subvert the expectations that those other films have instilled in viewers. Early in the film attractive deck hand Johnny (Jack Hickey) and Siobhán have a meet cute as he helps her aboard the Niahm Cinn Oir, but Hardiman’s screenplay immediately dismisses the idea of a romantic coupling when Siobhan takes an interest in the handiwork of the ship’s engineer (Ardalan Esmaili).

There is a disaster aboard the N-29, the other boat that Jarrod, Johnny and Siobhán visit in search of answers, but it’s not an opportunity for cheap jump scares. Similarly, there is an infection that begins to creep through the crew, but the victims, the symptoms and the reactions are atypical for this kind of tale.

Considering the title of the film refers to a kind of sea-based insanity that befalls crews trapped for long periods of time in close quarters, as well as the paranoia that accompanies the spread of the infection, it would be reasonable to assume that Sea Fever will eventually turn into a full-on murderous brawl for survival. But while there is a certain level of disagreement, the film never descends into warfare; Hardiman opts instead for tension and level-headed arguments.

The film’s conflict comes from a place of desperation, but the characters never cease to be less than real people – they’re not simple caricatures who lose their minds when their safety is threatened. They bicker, they attempt to rationalize their situation, and they plot, but they don’t suddenly become homicidal killers. Sea Fever refuses to go the easy, familiar narrative route of simply turning characters into monsters; Hardiman would rather make them face the human realities of their situation. This often means that the film is more of a high concept character drama than a horrific monster mash.

That is not to say that Sea Fever doesn’t still have fantastical elements, though. The barnacles are revealed to be caused by bioluminescent tendrils that have suctioned themselves to the boat. The tendrils are revealed to be attached to the larger monster that resembles a glowing squid. Blue goo regularly oozes from the porous patches onto the deck and is tracked about the ship ominously. And the infection has more than a few icky body horror symptoms, including a legitimately shocking and unexpected demise for one character early in the film.

Ultimately Sea Fever is a subversive, intelligent, adult aquatic horror film that prioritizes characters first and foremost. Writer/director Hardiman has crafted a smart film that is aware of the conventions of the subgenre and leans into those tropes as often as she eschews them. The film looks great, it has unexpected developments and there is plenty of mystery in the mythology, which has elements of both environmental allegory and government conspiracy.

While Sea Fever may not be the madcap monster aquatic horror film that some audiences anticipate going in, the result is far more introspective and thought-provoking.

This is one that will stick with you.

Editor’s Note: This TIFF review was originally published on September 19, 2019.