Ten complete strangers are invited to spend the weekend in a lonely mansion on an island off the English coast. Once there, they realize that none of them know their unseen host, who has identified himself only as "Mr. Owen." Using a prerecorded gramophone, Mr. Owen accuses them each of past murders that the law was unable to punish, and promises swift retribution. Soon thereafter the first guest dies, the victim of poisoning. The remaining guests come to realize that the killer is murdering them according to the old Ten Little Niggers nursery rhyme. When their attempt to locate Mr. Owen by searching the island proves fruitless, they realize that the unknown assailant is in fact one of them.