Ten people travel by
aerial tramway to a snowbound mansion, invited there by a Mr UN Owen (Unknown) to spend the weekend. They discover that none of them has actually ever met Owen, including his secretary as well as a married housekeeper and cook, all hired through an agency. Framed copies of the children's nursery rhyme "
Ten Little Indians" are hung on the walls of each guest's bedroom. Dinner is served by the butler Grohmann on a tray adorned with ten little Indian figurines, as well. At exactly 9 p.m., as instructed, Grohmann switches on a hidden tape recording. A man identifying himself as Owen reveals that each of the 10 guests has a scandalous secret, their involvement in various innocent people's deaths. One by one, the guests begin dying off. Mike Raven chokes after taking a drink and dies, and a small Indian figurine from the centrepiece tray is broken away. In the morning, the tram cable is cut, killing the cook, Mrs. Grohmann, who attempted to escape. General Mandrake conducts a search of the chalet's catacombs, splitting everyone into pairs, ultimately leading to his demise, stabbed after being led to a planted distraction (a cat). It becomes clear that their unseen killer is following the nursery rhyme. Ann Clyde, the secretary, enters into a romantic relationship with engineer Hugh Lombard as they and the others begin a deadly cat-and-mouse game, ultimately deducing that Owen is not their host but, in reality, one of them. After falling under suspicion from the others, Grohmann attempts to make his escape down the mountain peak, Devil's Leap, ending in his death after his lifeline is severed with an axe. Ilona bitterly confesses to having driven her husband to suicide, and is later found dead in her bedroom, killed with a syringe. By now, the five remaining guests fall under distrust of one another, and alliances are formed as the generator shuts down, casting the mansion into total darkness. At dinner, each person reveals the nature of their accusations, but before Ann can attest to her crime, she separates from the group to her room, where she screams upon discovering an Indian decoy hung from the ceiling. In the confusion, Judge Cannon is found with a gunshot wound to his head. Dr. Armstrong intimates his suspicions of Ann, which Lombard angrily rebuffs. Lombard later comes to Ann's room and confides that his real name is Charles Morley, and that the real Lombard, a friend of Morley's, had committed suicide. Sorting out Lombard's things, Morley found the invitation and decided to accept it, posing as Lombard, to see if he could throw light on why his friend killed himself. Morley gives Ann his revolver for her protection. In the morning, Blore discovers that Armstrong has vanished and the three conduct a search for him. Blore separates and goes outside, where he is crushed by a large statue of a bear. Ann and Morley discover the body of Dr. Armstrong in the snow and conclude that the killer can only be either of them. Ann pulls the revolver on Morley and shoots at him, before returning to the mansion. She goes upstairs and discovers Judge Cannon very much alive, who explains how he persuaded Dr. Armstrong to help him fake his death. He adds that he intends to poison himself, leaving Ann as the last remaining survivor, who must hang herself and fulfil the rhyme, or be punished by the law instead. As Judge Cannon is explaining his plan, having taken a fatal dose of poison, Morley reappears, alive. As he dies, Judge Cannon realises his plan has failed, and Ann and Morley kiss in relief. They see the cat sitting with the fruit tray, with only two Indians attached. ==Cast==