Terror by Night is a 1946 Sherlock Holmes crime drama directed by Roy William Neill and starring Basil Rathbone and Nigel Bruce. The story revolves around the theft of a famous diamond aboard a train. It is one of four films in the series in the public domain. The film's plot is a mostly original story not directly based on any of Arthur Conan Doyle's Holmes tales, but it uses minor plot elements of "The Adventure of the Empty House," "The Disappearance of Lady Frances Carfax," and The Sign of Four.