Outstanding student marine biologist Siobhán (Hermione Corfield) might be neuroatypical, or maybe just be ordinarily unsociable, but is more comfortable in laboratory conditions than out at sea. But in order to pass her course, she has to prove herself by taking a field trip on a small trawler operated by husband and wife team Gerard (Dougray Scott) and Freya (Connie Nielsen). Even before the shift to horror, writer-director Neasa Hardiman’s movie stresses how uncomfortable Siobhán is in these circumstances and how disturbing she is to everyone else aboard – we wince with her when she sees the primitive, messy conditions she’ll have to endure, but also see how irritating she is to struggling fisher-folk whose livelihood is being eaten away. Oh, and when Siobhán takes her cap off, her flaming red hair is taken by some crew-members – especially gaunt Ciara (the splendidly witchy Olwen Fouéré) – as a dire omen, though since this Irish-Swedish-Scots co-production is set in waters off the West of Ireland it’s a bit of a stretch that this superstition has persisted.
Like the farm-set Isolation, this is a very low-key Irish monster movie – it does eventually bring out the tentacles, but we spend at least as much time on the struggles of a traditional industry being run down as the horror business … and in the end things get out of hand because of hard choices taken for economic reasons rather than defying nature itself. Out at sea, Freya shows Siobhán turquoise bioluminescence in the boat’s wake and gives a folkloric explanation the scientist shrugs off – then, a strange, seeping, soft patch in the hull prompts investigation that reveals a sucker attached to the exterior, which turns out to be part of a large, as-yet-unclassified deep sea creature brought to the surface. We’ve seen quite a few semi-Lovecraftian entities in the movies lately, but this is the first instance where discovery prompts fisherman to get excited about how much the catch will bring in – before it turns out that the seepage carries microspores which are both fatal and highly infectious, and Siobhán becomes even more unpopular as she logically insists on quarantining the dwindling crew rather than heading for home port and risking the population at large. Withal, she sticks to scientific principals in regarding the tentacled thing as a rare animal rather than a monster – and so has to start watching her back when naked survival instincts kick in among her ship-mates.
Siobhán is an interesting, unusual heroine – evoking (and revising) such figures as Ripley in Alien and Dr Carrington in The Thing From Another World, and applying scientific, logical methods even when they imperil her own survival (she pointedly isn’t a final girl who’ll fight till she’s the last one standing). She has that quality of being right but infuriating, in that she was even right not to want to come on this trip. Corfield – whose diverse genre CV includes Rust Creek, Slaughterhouse Rulez and Pride and Prejudice and Zombies – carries the film, supported by reliables like Scott, Nielsen and Fouéré (who’s had a run of good ominous roles lately – The Survivalist, Beast, Mandy). The monster effects are sparing but workable, and Hardiman deploys the trappings of the traditional horror-of-the-sea yarn, which go back beyond Lovecraft to Melville or William Hope Hodgson.