Sherlock Holmes and the Secret Weapon

Sherlock Holmes and the Secret Weapon 1943 is the fourth in the Basil RathboneNigel Bruce series ofSherlock Holmes films which updated the characters created by Sir Arthur Conan Doyle to the present day. The film is credited as an adaptation of Conan Doyles short story The Adventure of the Dancing Men, though the only element from the source material is the dancing men code. Rather, it is a spy film taking place on the background of the then ongoing Second World War with an original premise. The film concerns the kidnapping of a Swiss scientist by their nemesis Professor Moriarty, to steal a new bomb sight and sell it to Nazi Germany. Sherlock Holmes and Dr. John Watson have to crack a secret code in order to save the country. The film is one of four films in the series which are in the public domain.

Tobel successfully demonstrates the bombsight for Sir Reginald Bailey Holmes Herbert and observers from Bomber Command. Tobel, now under the protection of Inspector Lestrade Dennis Hoey and Scotland Yard, tells Sir Reginald that, although willing to provide the British with his bombsight, only he will know its secret and has a complex plan for its manufacture to keep the secret safe. He separates his invention into four parts and gives one to each of four Swiss scientists, known only to him, to construct separately and whose names are unknown to each other. Soon after, Holmes receives a call from Lestrade telling him that Tobel has disappeared. Holmes goes to Charlottes flat, where he receives Tobels envelope. Rather than the coded message, the message inside is from Holmes nemesis, master criminal Professor Moriarty Lionel Atwill.Disguising himself as Ram Singh, one of Moriartys old henchmen, Holmes searches the Soho district for information. He encounters two henchmen Peg Leg Harold De Becker and Jack Brady Harry Cording, but is captured by Moriarty. Holmes is put into the false bottom of a sea chest, but is rescued when Watson and Lestrade observe the henchmen struggling with its unusual weight. Holmes returns to Charlottes flat to search for clues to the messages contents. He finds impressions of the message left on a notepad page by immersing it in fluorescent salts... and then photographing it by ultraviolet light. Holmes breaks the first three lines of a cunningly modified alphabet substitution code, which are the identities and locations of three of the scientists, but unable to break the fourth line, which has been altered as an added precaution, soon learns that Moriarty has murdered all three and stolen their parts. Meanwhile, Moriarty, also unable to break the fourth line, tortures Tobel for the name of the fourth scientist. Holmes deduces the change in the code and breaks the fourth line, identifying the scientist as Professor Frederick Hoffner Henry V

Source: Wikipedia