Who knows what this says about industry accessibility, but here’s a rare chance to see a genre movie directed by an actual peer of the realm. Randal Plunkett – 21st baron of Dunsany, interviewed in the Guardian this month – has taken leave from rewilding his estate to turn out a literary chiller about the relationship between a boozy blocked writer and the itinerant waif she takes in after a drunken car shunt. It’s the kind of potential folly that’s meant to have critics sharpening their knives. In fact, while it’s not devoid of first-feature fumbles and stumbles and carries over the movies’ traditionally wobbly estimation of How Writing Gets Done, The Green Sea’s stronger stretches invoke a wintry atmosphere that suggests Plunkett has spent his leisure time in the library with many of the right ghost stories. The smartest choice was made in the casting, with the deployment of Katharine Isabelle, Canadian star of the Ginger Snaps trilogy. Lending heart and spirit to Plunkett’s troubled scribe Simone, a snarly recluse in death-metal T-shirts that scream “keep your distance”, Isabelle also fosters a credible sisterly bond with newcomer Hazel Doupe; her response to news that her houseguest turned home help is a boyband aficionado proves winningly tart. Plunkett needs Isabelle because his plot is heavily backloaded: for over an hour, we’re puzzling over an indifferently paced character study, interrupted by jolting, decontextualised flashbacks, and brief cutaways to spooky figures spaced out along a distant shore, who represent either past trauma or nastiness lying in wait ahead. This deferral tactic isn’t necessarily a bad thing, but it means there’s a lot riding on the final half-hour; someone asks “what’s going on?” and Plunkett has to explain himself. What he lands on is surprising, and more eccentric than the film’s immediate influences would indicate. It’s also a touch clumsy around a pivotal reveal, and bound to set some viewers asking questions the writer-director doesn’t want to answer. In the moment, however, it sorta-kinda works, bolstered by the leads’ rapport, and cinematographer Philipp Morozov’s big-picture exteriors. Plunkett may well have resources enough to give himself a second shot behind the camera; his debut, the embodiment of a flawed-but-intriguing mixed bag, offers a fair bit to build on. The Green Sea is out now on digital platforms.