For a good half-hour in, The Signal is a slow burner. The crippled Brenton Thwaites, his girlfriend Olivia Cooke and best friend Beau Knapp are on a cross-country journey on the trail of an uber-hacker who taunts them by sending them pics and video of where they are. They trace him to a remote house, something unclear happens and then Thwaites wakes up in what appears to be a US government biological containment facility where he is being questioned by people, in particular Laurence Fishburne, who are inside hazmat suits. The questions keep perturbingly coming back to ones about alien abduction. Thwaites talks to his friend Beau Knapp through the ventilation grill where Knapp seems disoriented and confused, insisting that he has no legs. Thwaites then finds his girlfriend Olivia Cooke in a coma and tries to escape with her because he is wheelchair-ridden, this means towing the bed she is on behind his chair all the while trying to hide from people in the hallways.
At this point, The Signal seems to be heading towards somewhere between The Andromeda Strain (1971) and an alien abduction drama. Then things start to get weird. [PLOT SPOILERS] There is the supremely uncanny moment where Laurence Fishburne informs Brenton Thwaites that the friend he has been talking to through the grill only exists inside his own head. Things become completely bizarre after Brenton Thwaites is recaptured from his escape attempt, is placed in a hospital bed and falls out to reveal that both of his legs have been replaced by gleaming angular metal prostheses of what we are later told is alien design.
From this point onwards, The Signal becomes a film of constant unexpected carpet pulls from beneath the audience where the sense of reality and everything that is happening is constantly being thrown on its head. Brenton Thwaites and Olivia Cooke make an escape from the facility and through the town in a semi-trailer, only to discover that the highway abruptly ends at a vast artificial canyon around the town. It gets even weirder when, during their escape, they are picked up by kooky Lin Shaye who talks about angels coming down from above, before she is apprehended and questioned by Laurence Fishburne, seems to get caught in a feedback loop during the questioning and starts leaking purple goo from her ear before he opens a steel briefcase and pulls out a gun presumably to eliminate her.
[PLOT SPOILERS] The final revelations about who we are dealing with, who we think the authorities are and where everything is located is waaaaay out there. It turns what we think is a film about returned alien abductees into some completely bizarre variant on Dark City (1998). The main problem with the end revelation is that it shows we have a film constructed more in terms of a series of wild head-turning spins than one where we are ever given any strong underlying rationale for why things are happening. The end leaves us with a host of unanswered questions who are the abductors? What is the purpose of placing people into a simulation where they are led to believe they have been abducted by aliens? Why did Nomad lead these people in particular on a chase and then abduct and alter them? Who or what are all the other people in the simulation?