Murder by Decree (1979) is a classic mystery thriller starring Christopher Plummer, James Mason, and David Hemmings. Based on the works of Arthur Conan Doyle, the movie follows Sherlock Holmes' investigation of Jack the Ripper, where he unravels a conspiracy to protect the killer. Directed by Bob Clark and written by John Hopkins and Elwyn Jones, this cinematic masterpiece is sure to keep you on the edge of your seat.