Eight strangers, Vera Claythorne, Philip Lombard, William Blore, Dr. Armstrong, Emily Brent, General Macarthur, Tony Marston, and Judge Wargrave are invited to Indian Island. Upon their arrival they are welcome by Mr. and Mrs. Rogers, the butler and housekeeper who report that the host, Mr. Owen, will not arrive until the next day.
That evening, after dinner, they are stunned to hear a recording accusing them each of a specific murder. They compare what they know, and determine that know one knows Mr. Owen and that they were brought to the Island according to someone’s plan.
One by one, the guests mysteriously die, in the same fashion as the nursery rhyme, “Ten Little Indians”. To make matters worse, the boat that usually supplies the island with provisions does not show up. After searching the island, and taking every precaution imaginable, they cannot prevent the continuing string of murders. The survivors conclude that the killer must be one of them.
After a series of frightening events, Vera Claythorne and Lombard are the only survivors. Convinced that Lombard is the murderer, Vera shoots him. When she returns to her room, she finds a rope with a loose knot tied to the ceiling. She is suddenly overcome with guilt for her past actions (she let a boy drown) and she feels a strange compulsion to enact the last line of the nursery rhyme, so she hangs herself.
The murders remain a mystery to detectives until a manuscript in a bottle is found, explaining how Justice Wargrave killed the victims. He was dying of a fatal illness, and not wanting to slowly wasting away, he came up with a genius but disturbing plan. He had a desire for killing people, but he still had his principles in mind, so all of his victims were guilty of some murder, indirectly, however, so they were proven innocent by law.