W hen architect turned furniture store owner Clark ( Chiwetel Ejiofor ) finds a portal to a mysterious realm of “backrooms” in the basement of his showroom, he struggles to explain it to his therapist, Dr Mary Kline ( Renate Reinsve ).

“I found a place …”

This otherwise innocuous phrase becomes a chilling summary of the architectural horror conjured in Backrooms , the latest A24 thriller that takes us into the liminal spaces of offices, dead malls and other eerie places that exist neither here nor there. Kane Parsons, the 20-year-old director – the youngest ever to work with the studio – produced a series of YouTube shorts titled Backrooms using just the free 3D software Blender and Adobe After Effects. The series has now been turned into a feature-length film, although it retains its visual language and conceptual framework.

“Liminal spaces” are those places that seem to be in-between other places, or have been left behind by the world.…