An amnesiac man (Wes Bentley) wakes up following an accident to find a woman (Kate Bosworth) he doesn’t recognise standing over his bed, claiming to be his wife. But is she his carer or his captor?

Titled Unconscious in the UK but Amnesiac in the States, this slow-burn psychological horror thriller has echoes of Stephen King’s Misery yet very little of that film’s chilling suspense or dark humour.

It doesn’t help that Bosworth’s icy character is all too clearly up to no good from the start, making the story’s long-delayed twist revelation very much an anti-climax. Admittedly, director Michael Polish (Bosworth’s real-life husband) does deliver some very stylish touches. An aural match cut from what we anticipate will be a blow from a trepanning instrument to a knock at the door from an unexpected visitor proves a deft directorial trick.

And the sight of a fur-coat-wearing Bosworth wielding a blood stained power tool is a striking visual coup. The chillingly poised Bosworth keeps her cool throughout, too. Yet for the most part the story is too slackly stretched to sustain the tension the film needs to keep us gripped.

Certificate 15. Runtime 81 mins. Director Michael Polish.

Unconscious is available for download from 24th August and on DVD from 31st August, courtesy of Kaleidoscope Home Entertainment.