"And Then There Were None" is a mystery novel by Agatha Christie, first published in 1939. The story revolves around ten strangers who are invited to a remote island under different pretexts. Once there, they discover that their host is absent, and they are trapped with no means of escape. As the guests begin to die one by one, they realize that a mysterious figure is targeting them based on a nursery rhyme. The novel explores themes of guilt, justice, and the nature of evil, making it one of Christie's most acclaimed works and a classic in the mystery genre.