Cast: Katharine Ross, Sam Elliott, Roger Daltrey, John Standing, Ian Hogg, Margaret Tyzack, Charles Gray, Lee Montague, Hildegard Neil, Marianne Broome, William Abney, Patsy Smart, Mathias Kilroy, Reg Harding
In Los Angeles, Margaret Walsh (Ross), a young architect, has received a check for $50,000 from a British company she has never heard of. The check came in the mail with vague instructions of traveling to London for an interior design assignment. After making sure the check is legitimate, she convinces her boyfriend, Pete Danner (Elliott), to accompany her. Arriving in London, Margaret decides to take a tour of the English countryside before reporting for her assignment. She and Pete travel on a Triumph motorcycle over winding rural roads, enjoying the fresh air and old-world countryside. Suddenly, a black Rolls-Royce appears ahead. Pete turns sharply to avoid a head-on collision, loses control of the motorcycle, and he and Margaret careen off the road and end up lying on a field. They begin to pick themselves up and are joined by the passenger in the car, Jason Mountolive (Standing), and his chauffeur, Harry (Hogg). Mountolive is very polite and solicitous, checking that Margaret and Pete were not harmed. He invites Margaret and Pete for tea at his home. The motorcycle is damaged and cannot be ridden, and Margaret and Pete agree to Mountolive’s offer. On the way to Mountolive’s house, Harry stops at a village and tells a local mechanic where to pick up Pete’s motorcycle for repair. They ride in the Rolls-Royce on a private road past an outer gate and well-kept parkland before reaching the stately Victorian country house. Mountolive asks Margaret and Pete to go inside. The two Americans find themselves in a sumptuous mansion, with many spacious rooms. They are met by Nurse Adams (Tyzack), an imposing middle-aged woman dressed in white, who assumes they are staying overnight and leads them to an upstairs bedroom, its fireplace already lit. Mountolive is unavailable, no rental cars are to be had, and Margaret and Pete make the best of the unfortunate situation and settle in their luxurious room. They are lying in bed when they hear a helicopter that lands in the yard, bringing Karl Liebnecht (Gray), Barbara Kirstenburg (Neil), Jacques Grandier (Montague), and Maria Gabrieli (Broome). The four arrivals are guests of Mountolive, Europeans obviously familiar with the estate. Margaret and Pete meet them and a late-arriving guest, Clive Jackson (Daltrey), a music tycoon. The five guests, financially secure and successful at their chosen occupations, have been summoned by Jason Mountolive. They didn’t expect Pete’s presence, but refer to Margaret as “the sixth.” Nurse Adams tells Margaret that Mr. Mountolive would like to see her, alone. She escorts a bewildered Margaret upstairs to Mountolive’s special suite, fitted somewhat like a hospital intensive care unit, with medical monitors and an oxygen tent. Mountolive lies in bed, under a white covering inside the tent. He calls out to Margaret, and when she approaches he grabs her hand and slips an engraved ring on her finger. She catches a brief glance of Mountolive, ill, darker, much older than the man she met earlier, and then she faints. Back at the bedroom with Pete, Margaret finds she cannot remove Mountolive’s ring, a ring like the one worn by the other guests. Margaret and Pete’s plans to leave are thwarted by the death of one of the guests, Barbara, a champion swimmer who inexplicably drowns in Mountolive’s indoor pool. Mountolive is not well, and the guests seem to expect that he will die soon and that they have been summoned to learn of his last will and to receive his legacy. Margaret and Pete decide to leave an increasingly strange situation. When the house staff keep coming up with reasons to delay their departure, Margaret and Pete steal a drive in the Rolls-Royce and drive away, but eerily find that no matter what route they take they keep coming back. Margaret thinks that something unnatural is at play, keeping them there. A second guest dies an apparently accidental but suspicious death, and then a third is found dead. Margaret and Pete realize they must somehow discover what’s going on and find a way out of the place, because a supernatural power is methodically killing off the guests, and they may be next.