Opus (2011) Trailer
When the cast of Opus arrives to an empty house in the desert, none suspect foul play. After all, each of the seven cast members were hand-picked from online submission videos to be part of an unscripted horror film. But as their cast mates start to turn up murdered, the actors begin to turn on one another. The house is locked down from the outside, and the cast scrabbles to find the truth. Finally, they realize that the film is real, and that their deaths are being recorded by the killer himself.