Ti West ( The Innkeepers ) makes horror films that burn slow and pay off big. This found-footage effort, however, is (comparatively) spritely and much more effective in build-up than denouement. Two “immersionist” journalists (AJ Bowen, Joe Swanberg) accompany a photographer (Kentucker Audley) on a mission to save his sister (Amy Seimetz) from a happy-clappy cult.
What follows borrows so heavily from a genuine 1978 tragedy that it tips from intriguing dramatisation into empty reportage. The performances are excellent, the atmosphere tense, but West is too caught up in the facts to enlighten us further.