I don't understand why this film has such a low rating (currently 3.7). It is fast-paced and tense from the beginning, as the main character is plunged into a frightening environment and pursued by people without understanding what is happening to her. The audience is similarly unsure of what is going on, which makes for an intriguing situation and an exciting denouement as events unfold. The actor who plays the main character was apparently told nothing about the plot or what was going to happen to her, which makes the emotions she displays on screen very realistic. Ignore the reviews and watch this film.