In a sleek Philadelphia high-rise, an ordinary elevator ride descends into a waking nightmare. Five strangers, including a guarded security guard Logan Marshall-Green, a cynical mattress salesman Geoffrey Arend, and a troubled young woman Bojana Novakovic, find themselves trapped between floors. As the lights flicker and panic sets in, a chilling realization dawns—one of them is not who they appear to be. Detective Bowden Chris Messina, haunted by a personal tragedy, is called to the scene but can only watch in frustration as the situation grows increasingly dire and inexplicably violent inside the sealed cab. Guided by the ominous, religiously-inflected observations of a building security guard Jacob Vargas, the investigation becomes a race against time and a battle against a malevolent supernatural force. This tense and claustrophobic thriller, produced by M. Night Shyamalan, masterfully weaves suspense with a pervasive sense of dread, forcing both the characters and the audience to question every shadow and suspect every soul as the true nature of the evil among them is revealed.