Eight people, all strangers to each other, are invited to a small isolated island off the coast of
Devon, England, by a Mr and Mrs Owen. They settle in at a mansion tended by two newly hired servants, Thomas and Ethel Rogers (a married couple), but their hosts are absent. When the guests sit down to dinner, they notice the
centerpiece, ten figurines of Indians. Thomas puts on a
gramophone record, through which a man's voice accuses them all of murder: • General Sir John Mandrake – ordering his wife's lover, a lieutenant under his command, to his death • Emily Brent – the death of her young nephew • Dr Edward G. Armstrong – drunkenness which resulted in a patient dying • Prince Nikita Starloff – killing a couple while speeding in a car • Vera Claythorne – murdering her sister's fiancé • Judge Francis J. Quinncannon – being responsible for the hanging of an innocent man • Philip Lombard – causing the deaths of 21 South African tribesmen • William H. Blore – perjury, resulting in an innocent man's death • Thomas and Ethel Rogers – the demise of their previous employer, an invalid It becomes apparent that none of them knows or has even seen U. N. Owen and they realize the name stands for "unknown." They also cannot leave the island, as Rogers informs them that the boat will not return until Monday, and it is only Friday. Starloff admits his guilt, then dies after his drink is poisoned. The next morning, it is discovered that Mrs Rogers died in her sleep. The guests notice that one figurine is broken and another missing and with the two deaths matching the
Ten Little Indians nursery rhyme, they search the island for "Mr. Owen" without success. After General Mandrake is stabbed to death, the judge declares that Owen must be one of them. They vote on who they suspect Owen is; as the only person to get more than one vote, Rogers is made to sleep in the woodshed. The next morning, they find him dead, his head split open with an axe. Miss Brent dies next, her body found with a
hypodermic needle nearby. Armstrong discovers that his needle is missing, as is Lombard's revolver. At dinner, Quinncannon, Armstrong, Blore and Lombard all confess to their crimes. When it is Miss Claythorne's turn, she excuses herself to get her coat and the others hear her shriek and rush to her. In the confusion, a single gunshot is heard. They find her shaken after being brushed by seaweed hanging from the ceiling. They also find Lombard's gun, with Quinncannon dead from a shot to the head. Miss Claythorne insists she is innocent, but Armstrong suspects her and locks her in her room. That night, Claythorne admits to Lombard that her sister killed her own fiancé, and that Claythorne helped her cover up the crime and took the blame. The two later realize Armstrong is missing. The next morning, Blore is struck by stonework toppled from the floor above. Lombard sees a corpse on the beach, which turns out to be Armstrong. Miss Claythorne holds Lombard's gun against him, certain that he must be the killer. He tells her that his real name is Charles Morley, and that the real Lombard was his friend who committed suicide. Morley urges her to shoot but deliberately miss him – he then drops as if shot. She returns to the house and finds a noose hanging in the parlor and discovers that Quinncannon, who is very much alive, is the mysterious Mr Owen. The judge tells her that all his life he had searched for perfect justice. After learning that he was terminally ill, he concocted this plan. He persuaded Armstrong to help him fake his own death, then murdered him. He tells her that she can either hang herself or be sent to the gallows (as the only possible perpetrator). He then drinks poisoned whiskey, while Morley appears behind him, alive and well. Quinncannon dies and the boat arrives, rescuing Morley and Miss Claythorne. ==Cast==