There’s a smidgeon of Nicolas Roeg’s discombobulating 1973 classic Don’t Look Now in this spooky Northern Irish psyche-out.

Andrea Riseborough plays Laura, a grieving mother in a small town who becomes increasingly enamoured of Megan (Niamh Dornan), the young girl who moves in next door. Laura's mother (Eileen O'Higgins) is rightly unsettled by Megan's relationship with the neighbours, but not as unsettled as Laura becomes when Megan starts saying odd things. She can recall details about the local playground that Laura once frequented with her late daughter, Josie. She talks about the time "before" in a manner befitting the reincarnated.

Laura’s husband Brendan (Jonjo O’Neill) desperately tries to talk Laura around. “We all miss Josie,” he pleads. “But Megan is not Josie.”

Or is she? Megan’s drawings include a stick-figure sketch of a family that could pass for her neighbours. She has, additionally, crossed out the name over her school coat peg and written in “Josie”. These creepy details and Megan’s insistence on ketchup smiley faces unnerve Laura’s teenage son Tadhg (Lewis McAskie), who takes an immediate dislike to the little girl and soon falls out with the family next door, including Megan’s formidable-looking stepdad (Martin McCann).

Writer-director Stacey Gregg’s script stumbles a little around the film’s reveals and it doesn’t quite yield the deliciously malicious bad seed and gaslight mash-up that Megan’s character initially promises. Still, this is an intriguing psychological thriller and a carefully calibrated study of maternal mourning, powered by perceived class differences and harsh maternal judgment. The cast is great but Chloë Thompson’s camera seldom swerves from Andrea Riseborough’s layered central performance. Adam Janota Bzowski’s score adds to the creeping dread.