A 1939 Sherlock Holmes film produced by 20th Century Fox as an immediate sequel to their hit production of The Hound of the Baskervilles (1939) that premiered earlier in the same year. This is the second film to star Basil Rathbone and Nigel Bruce as Holmes and Watson and the first where they got top billing. It would also be the last film where they would be in a Victorian setting. After Fox lost the rights, Universal picked them up but they decided (probably for financial reasons) to have Holmes and Watson in the present day. In the meantime a radio spinoff was picked up, and Ratbone and Bruce would continue to play their parts in both mediums until 1946.
The credits claim the film is based off William Gillette's famous melodrama, but in truth it's an entirely original pastiche.
The films chronicles Sherlock's battle with his Arch-Nemesis Professor Moriarty. After barely getting off a murder charge at the Old Bailey, due to Holmes having the misfortune to uncover new evidence destroying Moriarty's alibi ... mere minutes after the jury has rendered their verdict of not guilty. Moriarty taunts Holmes that he's going to break him by pulling off the "Crime of the Century" and that Holmes will never suspect a thing until it's too late - then Moriarty can retire and devote himself to abstract sciences.
The next day Holmes gets two visitors: Sir Ronald Ramsgate, Constable of the Tower of London and the young heiress Ann Brandon. Sir Ronald comes with a letter that states that the next Crown Jewel to be added to the collection, the Star of Delhi will never reach the Tower. Ronald asks Holmes to be on hand when the jewel arrives. Miss Brandon comes with another letter - a drawing of a man with a bird hung around his neck that was sent to her brother. Ann and her brother have seen one like it before - their late father was sent one just before he was murdered. This of course entices Holmes who eagerly takes up the case, while Watson ruefully reminds him that Moriarty is still at large. And unknown to Holmes, Moriarty wants him on the Brandon case....
- Adaptational Wimp: In Conan Doyle's stories, Professor Moriarty's genius is that his criminal organization is so well-hidden that he is never caught, not even so much as even suspected and to the world, he's a respected retired academic. The film opens with him being put on trial for murder. He's acquitted due to lack of evidence but everybody knows he's a villain, they just can't prove it.
- All There in the Manual: The screenplay reveals two pieces of information not in the finished film:
- Holmes' evidence for destroying Moriarty's alibi that he was in the company of 300 fellows of the Royal Society at the time of the murder he's accused of is that he tampered with the master clock at the Greenwich Observatory to establish his alibi.
- The Brandon family killer is Mateo, a South American native whose father was killed by Ann's father for the mine that made the family rich. So with Moriarty's help he's been killing the rest of the Brandons for their father's sins.
- Anachronism Stew: The music hall song Holmes sings as part of a disguise "I Do Like to be Beside the Seaside" was written in 1907. The film takes place in 1894.
- Bat Deduction: When Holmes is trying to figure out what Moriarty's scheme he blurts own the words "crowning achievement". He then realizes that Moriarty is in the process of stealing the Crown Jewels.
- Batman Gambit: Moriarty's plan is presenting Holmes with a complex mystery and Holmes becoming so absorbed by it, that Moriarty can work on his real crime in peace.
- Battle Bolas: Bolas are used as a murder weapon by Prof. Moriarty's henchman.
- Beam Me Up, Scotty!: Averted, In-Universe. Holmes really does say "Elementary, my dear Watson" in this film.
- Beard of Evil: Moriarty has one. It becomes a plot point when Moriarty shaves it off to disguise himself.
- Berserk Button: Moriarty will not tolerate it if you forget to water his flowers. He considers it a crime even worse than his own killing of a human being.
- Common Nonsense Jury: The jury at Moriarty's trial is forced to find him not guilty. They know he's guilty but there's no evidence to prove it - they even ask God to forgive them for doing their lawful duty.
- Damsel in Distress: Ann Brandon. She comes to Holmes for help after her brother receives the same threatening note sent to her father prior to his death. Any moment she is out of Holmes' sight, she gets into trouble, and he has to save her. She also faints not once, but twice: the first time after discovering that she was too late to save her brother, and the second time being when the murderer finally reveals himself, and pursues her. Luckily for her, Holmes is right around the corner, and saves her before she becomes the final victim.
- Fatal Flaw: Moriarty's obsession with beating Holmes.
- In Name Only: The film is credited as being based off William Gillette's play Sherlock Holmes, but apart from having Moriarty as the villain, and sharing the characters Billy the Page Boy and Bassick, it has nothing in common with the famed play. It also has nothing in common with the Sherlock Holmes short story collection of the same name.
- Mean Boss: Zig-zagged with Moriarty. He's reasonably polite to his henchmen Bassick, but he's downright abusive to his butler Dawes.
- Never Found the Body: One of Moriarty's henchmen went missing doing a job that went bad.Moriarty: Oh poor Higgins. They found nothing but his boots.
Bassick: One boot.
- The Only One Allowed to Defeat You: Moriarty won't rest until he's broken and humiliated Holmes.
- "The Reason You Suck" Speech: After the jury is forced to acquit Moriarty, the presiding judge has some very choice words for the professor.Judge: Prisoner at the bar, you have heard the verdict. Under the law, no other verdict is possible. Yet, it is undoubtedly a gross miscarriage of justice. It is deplorable, Professor Moriarty, that a man of your intellectual attainments should be standing in the prisoner's box charged with the crime of murder. And in setting you free, I cannot in my conscience exonerate you. Let the prisoner be discharged.
- Villain with Good Publicity: Averted. This version of Moriarty is a well-known crook — akin to Al Capone, he's suspected of a hundred crimes but there's no evidence to connect him to any of them.
- Worthy Opponent: Holmes and Moriarty as usual.Sherlock Holmes: You have a magnificent brain, Moriarty. I admire it. I admire it so much I'd like to present it pickled in alcohol to the London Medical Society.
Professor Moriarty: It would make an interesting exhibit.
- You Are Too Late: The Judge says this word for word to Holmes, when he arrives with new evidence that would destroy Moriarty's alibi... mere minutes after the jury has delivered their verdict of not guilty.