The story begins with an odd but distinguished fellow arranging the death of an unseen person on a falling elevator. Next, a clergyman on a bicycle stops outside of an English country manor, the Bruttenholm estate, where a foxhunt is about to begin. This fellow looks oddly familiar.
The film jumps to after the hunt where the Bruttenholm family discusses the hunt. Lady Joselyn, the daughter-in-law of the estate owner. A retired MI5 officer, Sir Anthony, is with the family as a guest. One of the family, Adrian Messenger, asks the officer (George C. Scott) to look at 10 names on a list, a diverse list of men all over England. He is to look up the people on the list to see if they are still living. Adrian won’t divulge anything else about the list, but he must take a trip to America to investigate something.
Adrian is next seen at the airport. The clergyman is behind him checking his bag for the same flight. Le Borge is behind them also on the flight. The clergyman then visits the men’s room where he removes his disguise of contact lenses, wig, fake teeth and facial prosthetic. The film cuts to his wearing another disguise but leaving the airport as the clergyman is called over the loudspeaker for the flight.
The airplane burst into flames over the ocean. Adrian is on some wreckage, mumbling some disjointed words, overheard by Le Borge who also cling to the wreckage. Adrian dies from his injuries.
Investigators discuss the sabotage, definitely a bomb. Sir Anthony appears and recognizes the name of L e Borge from World War II. Sir Anthony provides the list that Adrian gave him. So far he has discovered six of the names are dead, all apparent accidents. They are told than another name on the list has recently died. This gets the government involved.
Sir Anthony visits LaBorge in the hospital, where Lady Joselyn is also there. Le Borge recites the words that Adrian said at the plane crash. While it makes no sense at the time, Le Borge visits Sir Anthony at him home where the words are displayed on the board. Le Borge recites the words again as Sir Anthony is able to better understand the meaning of words to see the right variation of some words and to form sentences. This gives the words a deeper meaning.
They go to the home of Adrian, but before they get there, the odd man hiding as Lady Joselyn arrives looking for something. The man says he is a neighbor who has dropped in to feed the cat. Le Borge and Sir Anthony soon arrive, but just miss the man’s departure.
They look through various papers and Adrian’s manuscript looking for something related to what Le Borge remembered. Le Borge begins to show interest in Lady Joselyn Dana Wynter). As they look, the odd man arrives an someone’s apartment. Meanwhile, Sir Anthony discovers something strange about a page in the manuscript, about Adrian’s time in Burma during the war. Sir Anthony surmises a name had been deleted from the manuscript. They go to the home of the woman who types the script. On the route they discuss the physical looks of the odd man, and the clergyman from the airport, they look very different.
When they arrive at the typist’s flat, they discover her dead. The government has run down the remaining names, only one is left. Slattery. Le Borge and Sir Anthony go visit Slattery, who is in a wheel chair running a tobacco shop with his mother. They find Slattery’s brother, who says his brother is dead. Sir Anthony hits a dead-end.
Slattery is drinking at a pub and sees a man that gives him pause, someone who looks like he’s in a disguise. Slattery is then killed by the man and dumped in the ocean. It turns out that Slattery was impersonating his brother to collect his disability pension. His mother revealed he had been in a prison camp during the war. They had been on a secret mission in Burma but captured. One of the men, a Canadian sergeant sold them out for privileges.
The theory is the Canadian murdered those on the list, for fear he will be found out, for something yet to come. Then Sir Anthony discovers a clue. Something from Adrian’s words. A variation of the spelling of the Bruttenholm name, is the same as the Canadian’s name, but pronounced differently.
It is tied to the linage of the Bruttenholm family inheritance, of Derek, Lady Joselyn’s son who is next in line to inherit the estate.
Out of the mist, a gypsy mysteriously delivers a horse as a present for Derek, from Adrian. The horse obeys certain commands. This is ahead of a fox hunt, where a stranger (Kirk Douglas) shows up to participate in the hunt. Sir Anthony participates in hunt, but Le Borge drives Lady Joselyn in a vehicle. Le Borge has presented his formal interest in Lady Joselyn.
The stranger, George Brougham, is the nephew of the Marquis of Gleneyre, head of Bruttenholm family. Sir Anthony and Le Borge know that he is the killer but must wait for Brougham to make a move. He says he ranches with a big spread, as he ingratiates himself into the family with a patchwork background of fakery, and social skills. “Evil does exist,” he says. “Evil is.”
Sir Anthony baits a trap, he asks Brougham to look over the typing problem in the manuscript, to see what reaction he gets. This alerts Brougham, after Sir Anthony says he will get Scotland Yard on the case. Brougham reacts by speeding up his plan, an making Sir Anthony a target.
Sir Anthony has Brougham’s real background, he is an actor, not a rancher. Brougham makes an excuse to go to London on business. He will miss the upcoming hunt but loans his horse to Sir Anthony.
At night, Brougham carries a drag along the route of the upcoming hunt to lay the fox’s scent for the dogs to follow. It ends at a rock wall where a farm implement with deadly sharp edges awaiting the leader of the riders, which would be Sir Anthony riding Brougham’s horse.
The hunt gets underway, with Sir Anthony suspecting trouble. A group of protesters against cruelty to foxes runs along the way. The camera dwells on some of the protesters, who appears to be wearing disguises.
Sir Anthony leads the riders, as expected. As the hunt approaches the rock wall, the farm implement is moved out of the way at the last moment. There is no more fox scent, so the hunt unexpectedly ends. Sir Anthony explains the problem, he went out earlier in the morning an picked up the scent of the drag. He uses a dog to identify the person who laid the drag. It is suspected that Brougham is among the protesters in disguise.The dog finds him, makes a run for it, jumping on Derek’s horse. Derek commands him to stop, throwing the rider who turns out to be Brougham, who is himself impaled on the farm implement on the other side of a rock wall.
The film ends, with various characters from the film shedding their makeup to reveal stars who portrayed them. Tony Curtis, Robert Mitchum, Burt Lancaster and Frank Sinatra. Several other characters from the film are revealed to have been played by Douglas.
Directed by John Huston (The Maltese Falcon, The African Queen), a fox hunting enthusiast, keeps the mystery going even when we know that Kirk Douglas is behind the crimes. Produced by Joel Productions, Kirk Douglas’ company.