Warning: All spoilers are unmarked.
The Adventures of Sherlock Holmes
A Scandal in Bohemia
The Dancing Men
The Naval Treaty
The Solitary Cyclist
The Crooked Man
- Asshole Victim: Inverted. At first Colonel James Barclay seems like a good man and a respected soldier who was tragically murdered. Then its revealed he set up an Uriah Gambit to get rid of his comrade Corporal Henry Wood so he could marry his girlfriend Nancy, and Colonel Barclays death was accidental. Nobody sheds a tear for Colonel Barclay, especially not his wife.
- Uriah Gambit: Then Sergeant Barclay purposely gave Corporal Henry Wood bad instructions for escaping their camp, leading to his capture and torture for years, hoping he would die. This is was so Sergeant Barclay could marry Nancy who was dating Nancy at the time. It was even Discussed when Nancy cries out the name David, liking James Barclay to King David who sent Uriah to the frontlines in hopes that he would die and David could marry his widow.
The Speckled Band
The Blue Carbuncle
- Christmas Episode: Played with. "The Blue Carbuncle" takes place on Christmas Eve and various characters including Holmes and Watson are seen celebrating the holiday or talking about their Christmas celebrations. However, the plot has nothing to do with the holiday except for the titular blue carbuncle being hidden inside a Christmas goose. Remove Christmas and change the hiding place to another livestock, and the plot will remain largely the same.
The Copper Beeches
The Greek Interpreter
- Adaptational Villainy: Sophy Kratides in the original story avenges her brother's death in the end. Whereas here she still remains loyal to her boyfriend even after learning that he killed her brother, which causes Sherlock to remark that she is cold and without compassion.
The Norwood Builder
- Faking the Dead: Jonas Oldacre fakes his murder and with plans to start a new life under a new name.
- Revenge by Proxy: Years ago, Jonass fiancée ended their engagement after seeing how cruel Jonas was and marries a man named McFarlane. Fast forward to the present, Jonas frames her son John Hector McFarlanefor his murder o of vengeance against his former fiancée.
- Starting a New Life: What Jonas planned to do if he werent caught by Sherlock Holmes and the police.
The Resident Patient
The Red Headed League
The Final Problem
The Return of Sherlock Holmes
The Empty House
The Priory School
- Adaptational Nice Guy: In the original short story, Duke of Holdernesse is so desperate to avoid scandal that he allows his kidnapped son to stay at an inn for three days after hes found before bringing him home and allows Hayes, one of the boys abductors, to flee justice. In the TV series, the Duke is also concerned about preventing scandal and demands the police to keep a low profile, but Sherlock Holmes talks the Duke into putting his sons life over his reputation and allows greater freedom of movement for the police and Sherlock Holmes to continue his investigation.
- Bastard Bastard: James Wilder - the bastard son of the Duke of Holdernesse and a woman of lower status named Francesca. The Duke raises James like a son but never acknowledges his relation to him. As a result James kidnaps his younger legitimate brother Lord Saltire to force the Duke into making James his heir instead of his brother. In addition, the Duke reveals to Sherlock that James liked having power over him, and the Duke tried to change his sons ways.
- Death by Adaptation: James Wilder falls to his death. In the original short story The Adventure of the Priory School, he leaves for Australia.
The Second Stain
The Musgrave Ritual
The Abbey Grange
The Man With the Twisted Lip
The Six Napoleons
The Sign of Four
The Devil's Foot
The Bruce-Partington Plans
The Hound of the Baskervilles
The Casebook of Sherlock Holmes
The Disappearance of Lady Frances Carfax
The Problem of Thor Bridge
Shoscombe Old Place
The Boscombe Valley Mystery
- Papa Wolf: John Turner towards his daughter Alice. Since Alice was a baby, he has been blackmailed by Charles McCarthy who provisions for himself and his son James in exchange for keeping Johns sordid past a secret. John complied, but when Charles demands that Alice marries James, John absolutely refused. He originally planned to talk to Charles and resolve the matter peacefully, but when he overheard Charles and James arguing over Alice, he murdered Charles to protect Alice and maintain his freedom. When Sherlock Holmes confronts John with the truth, John begs Sherlock not to reveal to Alice the truth because it will break her heart.
The Illustrious Client
- Adaptational Villainy: Downplayed. Baron Adelbert Gruner is a shameless philanderer and a murderer both in the original source material and the Granada adaptation, but in the original source material, he never threw oil of vitriol (sulfuric acid) at his ex-mistress Kitty Winters. In the TV adaptation, he did which permanently scarred her.
- Aristocrats Are Evil: Baron Adelbert Gruner. He murdered his previous wife (only being acquitted on a technicality) and threatened a woman to kill the only witness or suffer an acid attack, threw acid at Kitty, and is manipulating his current fiancée Violet de Merville into staying with him.
- Papa Wolf: Violets father General de Merville is very concerned that his daughter will be in mortal danger if she marries Baron Adelbert Gruner and has her meet with Sherlock Holmes and Kitty Winters in hopes they can convince her to break off the engagement. In a way, Sherlock Holmes himself. As he explains to Violet, he does not have a daughter, but if he had one, he would be just as concerned for her as General de Merville is of Violet.
- Reports of My Death Were Greatly Exaggerated: Downplayed. The newspaper greatly exaggerated Holmess injuries from an attack as near-fatal with Holmes falling gravely ill, but in actuality, they were only serious but survivable and no grave illness followed suit. Holmes merely stayed in bed for a few days to recover while taking advantage of the false report to retrieve Baron Adelbert Gruners book of conquests.
The Creeping Man
The Master Blackmailer
- Adaptational Angst Upgrade: In the original canon, Sherlock is cheerful by the end of the story, joking around with Lestrade. In the TV series, Sherlock is somber by the ending and asks John not to chronicle the case because it is too painful.
The Last Vampyre
- Adaptational Nice Guy: Downplayed with Jack Ferguson. In the original canon, Jack poisons his baby brother out of sheer jealousy. In the TV series, Jack poisons the maid because he suffers from delusions of being a vampire stemming from a childhood accident.
The Eligible Bachelor
The Memoirs of Sherlock Holmes
The Three Gables
The Dying Detective
- Related Differently in the Adaptation: In the original source material, Victor Savage and Culverton Smith are nephew and uncle, respectively. In the TV series, they are cousins.
The Golden Pince-Nez
The Red Circle
The Mazarin Stone
The Cardboard Box