Every family has a black sheep, someone’s who’s stretched those ties to breaking point. Deco (Eoin Duffy) certainly falls under that heading; a life-long wastrel, he’s long been banned from darkening the door of his terrifying Ma (Hilda Fay) and teenage brother Matt (Karl Rice), but up until this point he’s never started to catch fire when exposed to the sun. It turns out that a hen party have returned from Transylvania with a thirst for blood and Deco is the latest victim. Against his better judgement, Matt lets his brother in. But Deco’s always been unpredictable, with an inability to control his appetites. Is Matt in danger from his brother, or can he help Deco come to terms with his predicament, and mend their bond along the way?

Conor McMahon’s sweetly gross vampire comedy is an ideal scarlet aperitif for a festival. Its touchstones are many – Shaun of the Dead, early Peter Jackson, and Buffy among others – which leads to a generally undemanding but engaging time with familiarity in no way breeding contempt. What it does have is a lovely cultural specificity in its broad dialects and its earthy humour. Let the Wrong One In is at its very best when it’s picking at the relationship between the brothers, and Duffy and newcomer Rice locate the heart of the piece through the increasingly frenetic slapstick as unerringly as any vampire hunter. Speaking of which, Anthony Head shows up as a taxi-driver-cum-Van Helsing type who’s engaged to patient zero of the outbreak. Thankfully it’s more than just some cheeky stunt casting, with the Buffy icon sparking enjoyably off his younger co-stars. When it’s those three clattering the house to pieces – a great location and an inspired use of limited space – it’s close to brilliant. It does however unravel slightly when McMahon spreads his bat wings to incorporate the wider outbreak.

The film is chaotic for sure, but it feels like a contained pandemonium until the hen party’s attempts to lure the inhabitants of Dublin to a nightclub. While this is clearly intended to be the payoff, and is loaded with all manner of madcap bloodletting and delightfully icky practical effects, it does feel like it begins to hurtle somewhat off the rails. Its small-scale, almost bucolic atmosphere was where the film has its core. The diversion away from the flawed, but endearing characters with which we’d spent so much time, in favour of generic, pantomime evil (although vampire bride is always a strong look) doesn’t do the film’s impact any favours – and this is where further lessons could have been learned from Shaun of the Dead.

Despite this, Let the Wrong One In is fairly joyous festival fodder. Definitively tipped towards comedy than horror – it’s as much slapstick as anything, imagine The Three Stooges raised on a diet of Evil Dead II – it nevertheless doesn’t shy away from creative violence and gory set pieces. But it’s strangely in its simpler moments where it really finds its feet. Duffy and Rice have brilliant love/hate double act, and the scenes in which Deco’s new predicament impinges brutally on the suburban mundanity show a real creativity and willingness to push against the established boundaries of vampire lore. Conor McMahon is clearly above all else a genuine horror fan, and that comes across in a gleeful, earnest way.

Screened as part of Glasgow FrightFest at Glasgow Film Festival 2022