Backrooms Guide: Where to Watch, Cast and Runtime

The internet’s creepiest urban legend, now A24’s biggest hit ever

Backrooms started as a single photo on 4chan in 2019 — an empty, fluorescent-lit office space with yellow walls and no exit, captioned with the idea that you could “noclip” out of reality into it if you weren’t careful. Kane Parsons turned that one image into a YouTube analog-horror series as a teenager, and A24 then turned his series into a theatrical feature with Parsons, at 20, directing his own debut. It became A24’s highest-grossing film ever, which is a strange, specific kind of internet success story.

The film follows Clark (Chiwetel Ejiofor), whose basement furniture showroom turns out to have a doorway that shouldn’t exist, leading into the endless, identical rooms the internet lore describes. Renate Reinsve plays his therapist, and Mark Duplass, Avan Jogia and Lukita Maxwell round out the people who end up finding out what’s on the other side of that door. The film keeps the source material’s core unease — recognisable, mundane spaces that have stopped behaving like spaces should — rather than replacing it with a more conventional monster.

It opened in theaters May 29, 2026, had a brief rental window on Prime Video and Apple TV, and reached HBO Max on September 25. The production record has the full cast and crew. If you want another new release from the same stretch of the year, our Disclosure Day guide covers Steven Spielberg’s alien-conspiracy thriller, and our watch guide hub has everything else we track by release date.