A crew filming and producing a staged-paranormal tv show greet fans and an audience outside the bar where they are about to begin filming a new episode. The crew’s main individuals consist of Martha, Pippa, and Greg. Martha is the "medium," who pretends to talk to and see spirits on the show. Pippa and Greg assist in the production by giving the history of the location, asking questions, and furthering the script. Pippa and Greg also operate cameras and produce sound effects. Greg is Pippa’s husband; he is also a tv producer.
The first part of the show consists of interviews with the bar staff who describe the eerie conditions of the bar's cellar. Martha watches as Pippa and Greg talk to the staff. She feels the cold of the cellar and thinks of her family. Her mom, Iris, was a ‘true’ psychic who did not make much money for her gift.
Martha stops reminiscing and prepares for the second part of the program, which is a vigil. They set up equipment, like motion sensors and thermometers, to make the show seem scientific. This was Martha’s idea. Pippa tells the camera that the audience needs to remember that Martha is being brought into this space blind. That is, she has no prior information about the location and its history. Of course, in reality, Martha is an actress who has memorized a script, but she makes sure to destroy it before they film. Pippa slips into her on-stage presence where she becomes a “true believer” in their show.
They begin the show and Martha reveals only a bit of information to keep the audience engaged, combining fact with fiction.
Greg makes a comment while Pippa is preparing for the show about Martha’s expensive jacket. Martha says she is worth the salary that she is paid. Greg asks how many personal clients Martha has as a “medium.” She says that she has a lot. Greg jokingly tells her that they could easily reveal her as a fraud. However, Martha knows that this would come at the detriment of the entire show.
Martha remembers how she learned to act like a medium. Her mom, Iris, and her sister, Suki, both had the gift of being a medium. Iris and Suki used their gift in reading tarot cards, talking to clients, and acquiring spirit guides. Martha did not have the gift, but learned to read body language and to describe fake spirit guides.
Martha has a fake spirit guide for the tv show, David, who she says was a religious figure. The show begins in its pseudo fashion with Pippa asking Martha scripted questions. Martha moves through her usual gestures: walking slowly, touching the walls, pondering the history, and commenting on the surroundings.
The crew reveals the gruesome history of the place. It was used as a prison run by inmates. The cameraman trips over a crate. A bird flies out and breaks its neck after slamming into the ceiling.
Martha becomes ill with a migraine. She feels as if she may throw up. The show continues talking about the prison. The odor in the basement, that was originally present, increases. Martha vomits. The sensation of vomiting reminds her of the summer when her father died.
After her father passed, Martha became ill and vomited frequently. When she wanted the comfort of her dad, her mother said that he was there in the room. However, Martha could not see him, which her mother said was because of her blindness. Martha felt that she was left in the darkness in comparison to her mother and sister who had the medium gift.
The smell, which Martha identifies as death, also reminds her of her dying mother. When her mother was dying, people still came to her for advice. Her sister took over the medium business. Her mother told her that Suki would be fine, as she had the gift, but asked Martha what would become of her.
Martha returns to consciousness as Greg is shaking her and asking if she can hear them.
Her surroundings are different. The original cellar is there but there is another world superimposed upon it. This world is the past world of the cellar and has ghostly figures and gruesome happenings. She realizes this was how Iris and Suki saw the world.
She also understands that this prison was not run peacefully by inmates but by a violent gang. Greg becomes confused as she is going wildly off-script and wonders if she did her own research. She begins naming the members until she names Thomas the Knife. Greg corrects her and explains that his name is Thomas the Blade. He is happy she is coming back to the script. Martha continues in great detail about the prison’s history.
Eventually, Thomas the Blade appears to Martha. The crew can hear him but not see him. Martha tells them to back up. She explains that the energy isn’t residual, but it is active. This means that Thomas could hurt them. Martha explains that Thomas was king in the prison and mutilated females because he did not like women. Martha is upset that she came down unarmed even though her mother had taught her cleansing and protective rituals.
The lights go out. There are cries of pain. The lights come back on. Pippa has been mutilated by Thomas but is still alive. Martha covers her up, and an ambulance arrives and takes her away. Greg accuses Martha of hurting Pippa on purpose. The crew speaks with the police. A ghost companion goes with Martha and she realizes that she too, has the gift of the medium.