Terror by Night is a 1946 British Sherlock Holmes crime drama film directed by Roy William Neill and starring Basil Rathbone and Nigel Bruce.It was written by Frank Gruber. The story revolves around the theft of a famous diamond aboard a train. 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 Blue Carbuncle," "The Adventure of the Empty House," "The Disappearance of Lady Frances Carfax," and "The Sign of Four". In London, Vivian Vedder verifies that a carpenter has completed a coffin for her recently deceased mother's body, which she is transporting to Scotland by train. She boards the train that evening, as do Lady Margaret Carstairs, who owns and is transporting the famous Star of Rhodesia diamond; Lady Margaret's son, Roland; Sherlock Holmes, whom Roland has hired to protect the diamond; Inspector Lestrade, who is also worried about the diamond's safety; and Dr. Watson and Watson's friend Major Duncan-Bleek. Holmes briefly examines the diamond.