Following the recent sarin gas incident, Sarah and Josh have decided they need a holiday, and thus they’re off to Romania to look up an old friend of Sarah’s. As Josh tries to overcome his fear of flight, Sarah admits to him that she’s finally taken the step of selling her aunt’s house and market garden in Moreton Harwood. Juno Baker sorted out the details, the money has been deposited into her “Marie Samuels” account, and her belongings are waiting to be unpacked in her new flat, which used to belong to the late Claudia Coster. But all that can wait; now she and Josh are on their way to a small town in Romania, where Yolande Benstead retired when her brand of journalism became too controversial for her nervous editors. As it happens, the village is currently hosting an international peace conference, and Sarah wants to see this historic event first-hand.
Sarah and Josh take a taxi to Yolande’s home, a creepy Carpathian chateau which Josh compares to something out of Scooby-Doo. Yolande is delighted to see Sarah again, and after Josh and Sarah get unpacked and settle in, dinner is served and Sarah and Yolande catch up. There are no televisions in the house; Yolande is too far out to get a good signal, and she keeps abreast of the news via the papers and an old wireless in one of the bedrooms. She lives alone apart from her servant “Dmitri”, who turned up on her doorstep six months ago with no memory. Yolande has tried to help him remember who he is, but she fears tat he’s experienced something so traumatic that he may never remember what happened to him. She feels sure, however, that he is completely harmless.
Sarah and Josh retire for the night in separate rooms, but Josh tells Sarah to give him a shout if anything spooky happens. Sarah scoffs and retires to her room, which comes complete with a stuffed grizzly bear and the old wireless set which Yolande mentioned. However, her sleep is broken when the clock strikes three by an eerie, low-pitched hum, and by the terrifying shrieks and wails of a spectral apparition. Josh arrives to find Sarah screaming hysterically, and as she recovers, she claims to have seen a ghost...
The next day dawns bright and sunny, but Sarah is still shaken and can’t believe she actually saw a ghost. She tries to snap out of her mood by going for a walk around the village with the grumbling Josh. Meanwhile, Yolande speaks with Dmitri and tries again to find out who he is, but he seems particularly agitated today and insists that he can remember nothing. All he knows is that something unbearable happened to him -- and last night he hears a sound which he believes he’s heard before.
Josh and Sarah split up upon reaching the village; Sarah wants to explore the town, but Josh just wants a pint after the exhausting three-mile hike. Sarah finds her way to a local museum, where she meets another expatriate Brit, Christian Ian Abbotly. Abbotly won’t or can’t tell her what he does for a living, leading her to conclude he’s involved with the peace conference in some way, but he does offer her his business card and invite her to share a cup of coffee. While Sarah spends a pleasant afternoon in Abbotly’s company, Josh catches a taxi back to the house and finds Dmitri helping Yolande with the gardening. He also tries to find out what Dmitri knows about last night’s strange events, but gets no further than Yolande; however, he does get the strong impression that Dmitri is hiding something, perhaps even from himself.
That night, Yolande invites two more friends to dinner: Jack McElroy, the American delegate to the peace conference, and his young wife Candy. The five of them spend a very pleasant evening together, and it’s well past midnight by the time Jack and Candy take their leave. Candy is devoted to her husband, and Sarah considers him a very lucky man. But that night his luck runs out. As the clock strikes three, Sarah sees the same apparitions she did the previous night, but this time they’re not quite as terrifying as before... but in the McElroy’s home, Candy is literally frightened to death while preparing for bed. The next day, Sarah and Josh learn of Candy’s death. Jack is in a state of shock, and Sarah, furious, vows to learn the truth.
Sarah and Josh return to Yolande’s home, where Yolande is trying to calm the agitated Dmitri; last night, he actually managed to write something down on a piece of paper, until the sounds came and frightened the memory out of him again. Yolande finally admits to Sarah that things like this have been going on for months, but she’s wary of investigating; even after spending six years in the village, she is still regarded as an outsider, and if she calls in the police because she’s seen a ghost, she’ll never be accepted. This is the real reason she invited Sarah to stay with her.
Sarah and Josh return to the village to investigate, and while there Josh meets Abbotly. He doesn’t get along with the smug ex-pat and retreats to the bar, but Sarah accepts Abbotly’s invitation to dinner. Abbotly excuses himself as Josh returns with further information; it seems that quite a few delegates have seen apparitions similar to those which killed Candy, and the conference is being disrupted as a result. Is the entire village haunted?
Sarah decides to get positive proof one way or the other, and has Josh wire up her bedroom with audio and video recording equipment. Yolande is reluctant to risk Sarah’s life, but allows her to try this experiment anyway. That night at 3 a.m. the apparitions return, and this time Josh and Yolande see them as well when they burst into Sarah’s room to rescue her. Thunder rolls as they flee to safety, while elsewhere in the house, the terrified Dmitri is confronted by a very familiar figure. Yolande hears something like a muffled thunderclap and investigates, to find that Dmitri has been shot and killed.
The next day, Josh finds that the video equipment has burned out; they’ll need to rent another player to find out what’s been recorded. In the meantime, Sarah has another lead; Dmitri’s murder definitely implies he’s involved with whatever’s happening, and before he died he wrote down the name of a university department. Josh and Sarah drive to the university, where they finally learn Dmitri’s true identity; he was once known as Doctor Mikhail Berberova, and he was a professor in the physics department. Sarah and Josh question the department head, Professor Vodancski, who is shocked to learn of Berberova’s death. Berberova was doing brilliant work in the field of sonics until he vanished two years ago, apparently resigning his position to work on a top-secret project which he referred to in his notes as “Project CIA”.
Josh can’t quite believe what he’s become involved with, but for Sarah the pieces are starting to fit together. When she and Josh return and play back the video from last night, Sarah isn’t surprised to find that there’s nothing unusual on the tape; the spectres which so terrified her, Josh and Yolande simply weren’t there. Ordering Josh and Yolande to call the police if anything happens to her, Sarah prepares to keep a dinner date -- but first she and Josh pay one more visit to Jack McElroy to see if Sarah’s suspicions are justified. In the room where Candy died, Sarah finds an old radio receiver, just like the wireless set in her own guest room.
Sarah visits Abbotly at his home, and questions him about the peace conference, claiming that she’s heard it’s not going as smoothly as hoped. Abbotly evades her questions and leaves to fetch some more wine, and as soon as he’s gone Sarah searches the room -- and finds a tape with Berberova’s voice, a record of his notes and his personal doubts about Project CIA. Abbotly catches Sarah listening to the tape and holds her at gunpoint, admitting that he’s been using Berberova’s work to disrupt the peace conference but refusing to tell her who he’s working for. As Sarah suspected, Berberova had isolated certain low-frequency electromagnetic fields which affected people’s perceptions, creating the illusion of supernatural visitations and generating fear within their minds. Once his work was complete, Abbotly turned the ghost-wave on him, and eventually murdered him to keep him silent. He now prepares to shoot Sarah, but at the last moment Josh arrives, overpowers him and seizes the gun. Like Sarah, he worked out the truth when he realised that “CIA” stood for “Christian Ian Abbotly.” Sarah survived despite the old radio receiver in her room because Yolande’s house was too far out to receive a strong signal. With Jack’s guidance, the delegates agree to resume the conference after some time off; Abbotly’s mysterious employers have failed to disrupt the cause of international peace.