Sea Fever review – eerie horror plays like Alien on a boat

Riffs on Ridley Scott's seminal sci-fi horror Alien seem to generate at an alarming rate. This year already produced bloated Kristen Stewart vehicle Underwater, which sunk to the lowest depths in order to ask “What if Alien, but wet?” Now Irish horror-thriller Sea Fever arrives clinging to the same, well-worn premise, but with a minor difference: it's set on a boat.

Underwater might have squandered the talents of its star, but Sea Fever – though ultimately a bit underwhelming – is an Alien imitation that stays afloat. What a time to arrive, too: writer-director Neasa Hardiman could hardly have predicted that her low-budget horror about a woman's feverish attempts to stop people from touching one another for fear of contamination would come to replicate the events of the real world, yet here we are.

Siobhan (Hermione Corfield) is a loner scientist who's been left with no choice but to undertake a vaguely described field experiment out at sea. The trawler she's secured passage on is headed by grouchy captain Freya (Connie Nielsen) and filled with assorted misfits. Already considered a nuisance by the crew, things are made worse when a fisherman catches a glimpse of Siobhan's bright red hair. It's bad luck, he explains, suggesting she cover it up for the duration of the trip.

Turns out she'll need more than a hat to survive what's in store: soon enough the rickety vessel comes under attack by a number of strange and beguiling tentacles – though “attacked” might be the wrong word. Amidst the dankness and moody lighting of the battered trawler, the threat posed in Sea Fever is oddly passive for a horror film, its creatures – glowing, phantasmagoric jellyfish – acting not out of malice but biological necessity.

Quickly the Alien vibes – complete with a new, eye-popping twist on the iconic chest-burster scene – give way to set-pieces straight out of John Carpenter's The Thing. The crew can't tell who's infected, so who should they trust? As they fall victim to the parasite, one by one, it becomes clear that Sea Fever has no intention of breaking any moulds. Yet the film's low budget serves to enhance its eerie aesthetic where a bigger one might have reinforced its genericness. The acting, low-key and unshowy, brings a gritty realism, whilst the mumbly dialogue and lack of traditional heroics contribute to a film that seems refreshingly indifferent to the fates of its characters.

Less impressive is the way Sea Fever refuses to fully engage with the more interesting ideas it throws out. When Siobhan tries to persuade the crew against returning to the mainland for fear of infecting the wider population, you wonder why the film doesn't do more to pit her against her shipmates. A more daring thriller might have leaned into this dynamic by repositioning the scientifically-minded Siobhan – desperate to prevent a global pandemic – as the film's surprise “villain.” The film we get instead offers a diverting and worthwhile take on a familiar idea, but one that ends up treading too much water.

Sea Fever is available on Blu-ray and VOD platforms from April 24.