Arthur Flitwick returns home with a phone he has found and wishes to return it to its owner. He calls the last number dialled, Moira O'Keefe. She says it belongs to Elsie Mitchelle, and advises Arthur to contact the local vicar, Reverend Neil. That evening, Neil enters the house, enquires how Arthur found the phone, and attempts to collect it. Arthur says he prefers to keep the phone and return it to Elsie; Neil leaves.
Technical issues arise, and the characters are inaudible. An announcer apologizes for the issues with the sound. The issues are unfixable, and "A Quiet Night In" is rerun to replace the timeslot. During the rerun, a ghost stands at the house's window. The ghost bangs on the glass and the feed glitches before cutting back to the now empty set of Dead Line. The announcer apologizes once again, but is cut off by intermittent whispering. She asks "Is someone there?", and then she screams.
The episode cuts to live CCTV footage of the set. It then suddenly cuts to footage of a real live broadcast that went wrong. On an episode of Public Enemy Number One (1992), Bobby Davro was put in stocks. The stocks fell, and Davro's face was smashed into the floor, which nearly killed him.
The episode cuts to live CCTV footage of the makeup room. Steve Pemberton (who plays Arthur) and Shearsmith (who plays Neil) complain about the technical issues, and the concept of the episode being live in general.
A clip from an episode of Most Haunted is suddenly broadcast, discussing the hauntings that occur within Granada Studios, where "Dead Line" is being filmed. It then cuts back to studio footage of the phone ringing. Stephanie Cole (who plays Moira) answers it and talks for a while with an unknown person. Meanwhile, Pemberton and Shearsmith learn they are being broadcast while reading about various historical disasters that occurred in Granada Studios.
Rehearsal footage of the episode is shown. Arthur is covered in blood in his bathroom, holding a knife, as Moira helps herself into his apartment after she received a message from Neil. Arthur hastily dresses up, and denies that he ever met with Neil. Moira discovers Neil's head inside the microwave. Arthur claims that Elsie's ghost contacted him through her phone, and that Neil murdered Elsie for money from her will. Breaking character, Cole asks Pemberton and Shearsmith about the characters' motives. A ghostly figure is visible behind them.
Cutting back to live footage of the set, Shearsmith comes to talk with Cole. She is possessed, and she says that the studio belongs to the ghosts and they are trespassing, advising Shearsmith to leave. Indifferent, he goes to make a cup of tea, and Cole kills herself by slicing her neck. CCTV footage from elsewhere in the studio shows a water bucket falling over by itself, and television screens shutting off. The Most Haunted episode is then played, where they discuss that just opposite Granada Studios, the Church of St John's has a graveyard with 22,000 bodies.
The broadcast cuts to Shearsmith's bodycam, making tea. He hears banging and investigates. It turns out to be Pemberton, who jump scares Shearsmith with the prop of Neil's head. Pemberton accidentally touches the water spilt from the bucket, and he is electrocuted and paralyzed.
The episode cuts to a fake news report. Alan Starr had hanged himself in Granada after experiencing schizophrenic episodes and paranormal incidents. He recorded voices of a spirit saying "let us be". The episode then cuts to an actual news report of a fire at Granada Studios. It caused costumes, sets, and props stored in Granada, which were meant for The Jewel in the Crown (1984), to be all destroyed.
The episode cuts back to Shearsmith, running to find help. The studio is now abandoned, and the lights go out. He is then jumped at by the spirit of Alan Starr, and falls to his death. Granada's other spirits look down at Shearsmith.
An interview on The One Show with Shearsmith and Pemberton is played, where Shearsmith denied the existence of ghosts. A scene from "A Quiet Night In", where Shearsmith and Pemberton's characters get shot, is repeated at increasing speed. The episode cuts to black, and a whisper is heard: "Let us be".
