Summary
Highlights
Dr. Watson recounts his medical career, his service in the Second Afghan War, where he was wounded and contracted enteric fever, leading to his return to England. Suffering from financial difficulties and loneliness in London, he reconnects with an old acquaintance, Stamford, who suggests he find lodgings with a peculiar but brilliant individual named Sherlock Holmes, a master chemist with an eccentric interest in out-of-the-way knowledge. Watson eventually meets Holmes, who immediately deduces Watson's service in Afghanistan.
Watson and Holmes secure lodgings at 221B Baker Street. Watson observes Holmes's erratic habits and his vast but specialized knowledge, which perplexes him. Holmes reveals his profession as a consulting detective, and demonstrates his unique method of deduction by accurately discerning details about Watson's past from seemingly trivial observations. Holmes's unusual skills are further highlighted when he makes an accurate deduction about a passerby, a retired sergeant of marines, much to Watson's astonishment and Stamford's amusement.
Holmes receives a telegram from Inspector Gregson about a perplexing murder at 3 Lower Candens in Brixton. A man named Enoch J. Drebber of Cleveland, Ohio, has been found dead in an empty house with no obvious cause of death, but with bloodstains on the floor. Holmes demonstrates his deductive prowess by providing a detailed description of the murderer and his mode of transport, much to the skepticism of Inspectors Gregson and Lestrade, who are already on the case. Holmes also quickly deduces that a mysterious word 'Rache' written on the wall is German for 'revenge', not a woman's name as Lestrade initially suspects.
Holmes and Watson travel to the crime scene where Holmes meticulously examines the area outside the house, noting clues like cab tracks and distinguishing footprints. Inside, he briefly examines the victim's body and the room before collecting a crucial item: a wedding ring found near the body. They then visit Constable Rance, who discovered the body. Holmes astounds Rance by recounting his movements inside the house, revealing additional details that Rance had not. Holmes believes Rance's encounter with a 'drunk' man at the scene is significant. Holmes reveals his intention to bait a trap using the wedding ring.
Watson recovers from the day's events, reflecting on the victim's sinister appearance and the puzzling circumstances of the murder. Holmes, after returning from a concert, explains his thought process regarding the case and reveals he placed an advertisement for the missing wedding ring, hoping to lure the perpetrator. He anticipates the 'florid friend with the square toes' will attempt to retrieve it. A seemingly old woman arrives, claiming the ring belongs to her daughter. Holmes, however, deduces she is an accomplice in disguise and follows her, but she eludes him by faking her destination and vanishing from her cab.
The press speculates wildly about the Brixton mystery, often focusing on political motives. Holmes shows amusement at the police's conventional theories. Wiggins, the leader of Holmes's street urchin network, reports no progress on a specific inquiry. Inspector Gregson arrives, triumphantly announcing the arrest of Arthur Charpentier, the son of Mrs. Charpentier, the victim's landlady. Gregson's theory is that Charpentier murdered Drebber after an altercation involving his sister. However, Lestrade then arrives with the shocking news that Joseph Stangerson, Drebber's secretary and Gregson's primary suspect, has also been murdered, with the word 'Rache' again found at the scene, throwing Gregson's theory into disarray.
Lestrade recounts the grim discovery of Stangerson's body, revealing Holmes's earlier prediction of 'Rache' was correct. Holmes examines two pills found near Stangerson's body, and using an ailing dog, demonstrates that one was deadly poison. He reveals that the second victim was killed by poison, not a stab wound. Holmes explains that details which perplexed others only clarified the case for him. He announces he knows the killer's name, Jonathan Hope, and plans to capture him. Hope, disguised as a cab driver, arrives at Baker Street, lured by Holmes, and is dramatically apprehended after a violent struggle, confirming Holmes's deductions and leaving a bewildered Gregson and Lestrade behind.
Dr. Watson recounts his return to Baker Street and finds Sherlock Holmes injecting himself with cocaine. Watson expresses concern about Holmes's drug use, prompted by Holmes's periods of intellectual stagnation. Holmes justifies his use of stimulants by stating his mind 'rebels at stagnation' and requires constant challenges. He dismisses Watson's previous account of the 'Study in Scarlet' as too romanticized. Holmes highlights his expertise in minute observation, demonstrating this by accurately deducing several details about Watson's recent activities and habits, and then applies his methods to an old watch belonging to Watson's brother, revealing a detailed history of its owner.
Mary Morstan visits Holmes, presenting an extraordinary case. Her father disappeared ten years ago after returning from India lacking any trace of him, a situation linked to Major Sholto, a friend of her father's. Six years ago, she began receiving a valuable pearl annually, sent by an unknown benefactor. She has now received a cryptic letter instructing her to meet an 'unknown friend' at the Lyceum Theatre to receive 'justice,' but warns against bringing the police. Holmes deduces the letter writer's identity and background through paper analysis and grammatical quirks, confirming a Bohemian connection. Holmes, Watson, and Mary plan to attend the mysterious meeting.
Holmes, Watson, and Mary Morstan arrive at a suburban house and are greeted by a Hindu servant. They meet Thaddeus Sholto, an anxious and nervous man with unusual physical traits, who immediately requests Watson's medical opinion. He reveals himself to be Major Sholto's son and the sender of the pearls. He recounts his father's mysterious death and the discovery of a paper inscribed with 'The Sign of the Four,' which perplexed him and his twin brother Bartholomew. He also explains that his father finally confessed to the circumstance of Captain Morstan's death before his own demise, linking it to the legendary Agra treasure. Thaddeus then reveals he has now discovered the treasure and desires to give Mary her rightful share.
Thaddeus Sholto, Holmes, Watson, and Mary travel to Pondicherry Lodge, Major Sholto's former home. Upon arrival, they are met by a gruff porter, McMurdo, who initially denies them entry until Holmes, leveraging a past acquaintance with McMurdo, gains access. Thaddeus grows increasingly apprehensive as they approach the house, which appears dark and silent. They hear a woman's distressed cries, identified as Mrs. Bernstone, the housekeeper. They find Bartholomew Sholto dead in his chemical laboratory, with a grotesque smile on his face, a poisoned dart near his ear, and a note 'The Sign of the Four' pinned to his body. Thaddeus realizes the treasure chest is missing.
Holmes immediately begins his meticulous investigation at Pondicherry Lodge, quickly deducing that an accomplice, a wooden-legged man, entered through the window and then used a rope to ascend to the attic where the treasure was held. He finds bloodstains on the rope and footprints of a wooden leg on the window sill. Investigating the attic, Holmes discovers tiny, naked footprints, leading him to believe an accomplice of extremely small stature was also involved. Holmes then determines from the victim's rigidity and facial expression that he died from a powerful alkaloid poison, likely from the dart he found. Inspector Athelney Jones arrives, arrests Thaddeus Sholto, and dismisses Holmes's insights, leading Holmes to tell Watson to get a dog named Toby that could trace the scent.
Watson takes Mary Morstan home, reflecting on his growing affection for her, but also his feelings of class-based inadequacy due to her potential inheritance. He then retrieves Toby, a keen-scented dog, from Mr. Sherman. Upon returning to Pondicherry Lodge, Holmes, wearing his stained boots, guides Toby to follow the unique creosote scent from the footprints found at the crime scene. Toby leads them through London's streets, eventually arriving at Smith's Wharf, a boat rental establishment by the Thames. There, Mrs. Smith reveals her husband and son left with a wooden-legged man in their steam launch, the Aurora, stained with creosote, and had not returned. Holmes then hypothesizes the perpetrators changed their mode of transport via the river.
Holmes, after explaining to Watson how crucial it is to extract information from reluctant witnesses by feigning disinterest, sends Watson home to rest. Holmes then alerts Wiggins to mobilize the 'Baker Street Irregulars' (his network of street children) to search for the Aurora. Meanwhile, Jones, who had confidently taken over the case, arrives at Baker Street, admitting his theory has faltered and the arrested suspects have alibis. Holmes, disguised as an elderly seaman, tricks Jones into revealing that a 'clue' about the Sholto gang has been picked up in Poplar and arranges for a police steam launch to pursue them. Holmes shares his deductions that the culprits are hiding the Aurora nearby, waiting for an opportune moment to escape London with the treasure.
Holmes, Watson, and Jones embark on the police launch, pursuing the Aurora down the Thames. Holmes deduces that Jonathan Small and his accomplice would have concealed the launch and themselves to avoid suspicion after the murder. Their strategy is to intercept the Aurora when it leaves its hiding place, as Small, being shrewd, would not keep it at a public wharf for long. As they pass Jacobson's Yard, their street irregular spots the Aurora. A high-speed chase ensues down the river. During the pursuit, they identify Jonathan Small, a one-legged man at the Aurora's helm, and his small, savage accomplice, ultimately revealed to be Tonga, an Andaman Islander. Holmes and Watson open fire, and Tonga is killed. Small, marooned on a mud bank, is captured, but not before throwing the treasure chest into the Thames.
With Jonathan Small captured, Holmes, Watson, and Jones return upstream with the recovered iron chest. Small recounts a brief, unapologetic version of events, emphasizing that Tonga killed Sholto, not him, and expressing regret for the outcome. Jones disembarks to take Small to the station. Watson, with his share of the treasure promised to Mary Morstan, is dropped off to deliver the chest to her. He reflects on his complicated feelings about her impending wealth and his own honorable intentions. He arrives at Mary's home, where she tells him the chest is empty, having been opened and its contents removed. This surprising turn removes the financial barrier between them, and Watson, overjoyed, confesses his love for Mary, who accepts and reciprocates.
Jonathan Small, now in Holmes's lodgings, confesses his entire story. He recounts his early life as a ship's carpenter, losing a leg to a crocodile in India, and becoming an overseer. During the Indian Mutiny, he found himself guarding a fort at Agra with three Sikh soldiers: Abdullah Khan, Mohamed Singh, and Dost Akbar. They conspired to murder a wealthy merchant, Akhmet, who was bringing a treasure chest, belonging to a Raja in the northern provinces, to the fort for safekeeping. They swore an oath to share the treasure equally among the 'Sign of the Four.' Small graphically describes Akhmet's murder and how they hid the treasure within the fort. Their scheme was discovered, leading to their arrest and penal servitude in the Andaman Islands.
In the Andaman Islands, Jonathan Small gained the trust of Doctor Somerton, a prison official, and formed a bond with Tonga, a native Andaman Islander. Small, with Tonga's help, meticulously planned and executed his escape aboard a canoe, murdering a prison guard in the process. He spent years wandering the world, driven by a desire for revenge against Major Sholto and Captain Morstan, who had double-crossed him and stolen the Agra treasure. Small tracked Sholto to London and, with Tonga's aid, finally retrieved the treasure, leaving 'The Sign of the Four' as his calling card. He then planned to escape to Brazil in a steam launch, but Holmes and Watson thwarted his escape, and the treasure was ultimately cast into the Thames. Small expresses no remorse for his actions, only for the lost treasure, detailing his hard life and the injustice he feels. He also asserts that his accomplices, the Sikhs, would have approved of his actions.
Dr. Watson reflects on his recent distance from Holmes since his marriage, and Holmes's eccentric life balancing drug use with intense criminal investigations. Watson visits Holmes and finds him engrossed in a new, intriguing case. Holmes introduces a disguised client, who reveals himself to be Wilhelm Gottsreich Sigismund von Ormstein, the hereditary King of Bohemia. The King explains that he had an affair with Irene Adler, a famous opera singer, five years ago and fears she will use a compromising photograph of them to prevent his upcoming marriage to a Scandinavian princess. He has been unable to retrieve the photo through various means, and Irene threatens to send it on the day of his betrothal, offering Holmes carte blanche to recover it.
Holmes, disguised as a stable-hand, observes Irene Adler's townhouse, Briony Lodge. He gathers information about her habits and her relationship with Godfrey Norton, a lawyer. He witnesses Norton and Adler rush to St. Monica's Church and get married in secret, with Holmes himself unwittingly serving as a witness due to a legal formality. Holmes then devises a plan to discover the photograph's hiding place. He disguises himself as a clergyman, enlists Watson as an accomplice, and stages a false fire alarm at Briony Lodge. His theory is that Irene's instinct, believing her house is on fire, will lead her to rush to the object she values most – the photograph. The plan works; she reveals the hiding place, and Holmes, having observed it, escapes.
Holmes and Watson return to Briony Lodge with the King to retrieve the photograph. They find that Irene Adler has fled the country with her new husband. Instead of the incriminating photograph, Holmes finds a letter addressed to him from Irene, revealing she saw through his disguise and the fire trick. She assures him the photograph will not be used to harm the King but will be kept as a safeguard. She also encloses a photographic portrait of herself. The King is relieved the photograph of him and Irene is safe. Holmes, however, keeps Irene's photograph as a memento of the woman who outwitted him, a rare instance of his plans being foiled by someone else's cleverness.
Dr. Watson visits Holmes and finds him with a client, Mr. Jabez Wilson, a portly, red-headed pawnbroker. Holmes introduces Watson, highlighting his love for the unusual. Deductions by Holmes regarding Wilson's past, based on his appearance, astonish Wilson. Wilson then recounts how his assistant, Vincent Spaulding, brought an advertisement from 'The Red-Headed League,' offering a well-paid and easy job to red-headed men. Despite initial skepticism, Wilson, encouraged by Spaulding, applies. He is hired by Duncan Ross to copy the Encyclopaedia Britannica for four pounds a week, under the strict condition he never leaves the office during work hours. After eight weeks of this peculiar work, the League abruptly dissolves, leaving Wilson perplexed and worried about the lost income.
Holmes immediately recognizes the gravity of Wilson's story. After some thought, he determines the purpose of the Red-Headed League was to keep Wilson occupied and out of his shop for several hours a day. Holmes then visits Wilson's pawnbroker shop, observing its surroundings and particularly the worn knees of Vincent Spaulding's trousers. He discovers that the shop backs onto a major bank. Holmes, after attending a concert, enlists Watson, Inspector Peter Jones of Scotland Yard, and Mr. Merryweather, a bank director, for a night expedition. He reveals his theory: the Red-Headed League was a diversion to allow Spaulding, identified as the notorious criminal John Clay, and an accomplice to tunnel into the bank's vaults. Holmes anticipates the robbery will occur that night, a Saturday, to allow extra time for escape.
Holmes, Watson, Jones, and Merryweather wait in the bank's cellar in complete darkness. Holmes explains his deductions that the tunnel leads from the pawnbroker's cellar to the bank vault. After a tense wait, a stone slab lifts, revealing a light and a hand. John Clay, along with his accomplice, emerges from the tunnel. Holmes and Jones capture Clay, while the accomplice escapes back into the tunnel but is apprehended by police waiting at the pawnbroker's shop. The robbery is foiled, and Clay, despite his capture, maintains an air of aristocratic defiance. Holmes explains his reasoning to Watson during a post-case discussion over whiskey, detailing how he pieced together the clues, recognizing Clay's ingenious plan to create a diversion and tunnel into the bank for gold.
Holmes, in a rare moment of philosophical musing, discusses the strangeness of life over fiction, illustrating with examples how real-life events often defy imagination. A new client, Miss Mary Sutherland, arrives to consult Holmes about the disappearance of her fiancé, Mr. Hosmer Angel. Holmes quickly observes details about Miss Sutherland that reveal she is a typist with poor eyesight. She explains that her stepfather, Mr. James Windibank, disapproved of her social life. She met Mr. Angel at a ball, and despite her stepfather's initial objections to her attending social events, he surprisingly went away on business, allowing her to further her acquaintance with Mr. Angel. Mr. Angel was a shy man, preferring to meet in the evenings and writing typewritten letters to avoid office gossip.
Mary Sutherland recounts that Mr. Hosmer Angel proposed marriage, insisting on fidelity regardless of future events. Her stepfather, Mr. Windibank, again conveniently went away. On their wedding day, Mr. Angel arranged for separate cabs for himself and the ladies. When they arrived at the church, Mr. Angel mysteriously vanished from his cab before reaching the door. Despite her profound sadness, Mary is convinced he will return and remains faithful, rejecting other suitors. Holmes, after Mary leaves, reveals his suspicion that the case is straightforward, noting peculiar details like the typewritten letters and signature. He concludes that Mr. Angel's disappearance was a deception, and to confirm, he writes to Mr. Windibank, inviting him to Baker Street.
Mr. James Windibank arrives, seemingly dismissive of Mary's concerns. Holmes reveals his deductions: the typewritten letters from 'Hosmer Angel' exhibit the same unique defects as Windibank's own typewriter. Confronted with this evidence, Windibank drops his gloves. Holmes locks the door, accuses Windibank of being Hosmer Angel, and outlines the scheme: Windibank, disguised as Angel, wooed his stepdaughter to prevent her from marrying and taking her inheritance, which he and his wife enjoyed. He orchestrated the 'disappearance' to keep Mary loyal and avoid losing her income. Sherlock Holmes, unable to legally punish Windibank, chastises him verbally, letting him flee, content that he has solved the case, but expressing regret for the lack of legal recourse.
Sherlock Holmes summons Watson to assist him in the 'Boscombe Valley Tragedy' in Herefordshire. During the train journey, Holmes explains the case: John Turner and Charles McCarthy, two Australians who knew each other from the colonies, settled near each other in England. McCarthy is found murdered near Boscombe Pool. Evidence points strongly to his son, James McCarthy, who was seen quarreling with his father and found beside the body with bloodstained clothes. James's own account is confusing, with a dying reference to a 'rat' and a refusal to discuss the cause of the quarrel. Holmes finds the circumstantial evidence against James unsettlingly strong but hints at inconsistencies dismissed by the police investigator, Lestrade. Holmes assures Watson he will either confirm or disprove the theory.
Holmes and Watson meet Lestrade in Ross, Herefordshire. Holmes, despite Lestrade's skepticism, is adamant he will uncover the truth. They are soon joined by Miss Alice Turner, daughter of Mr. John Turner, the wealthy landowner and McCarthy's old friend. She pleads with Holmes to believe in James McCarthy's innocence, revealing a secret: James and his father had constant disagreements, likely about her, and her own father, Mr. Turner, is also against their union. Holmes and Watson then travel to Happily Farm and Boscombe Pool, the crime scene. Holmes meticulously examines the ground, identifying footprints of the victim, the son, and a third, unknown individual who limps and is left-handed. He finds a cigar butt and a stone, concluding they are part of the murder weapon and evidence of the killer. He tells Lestrade he has solved the case, but Lestrade remains skeptical.
Holmes reveals his theory: the murder weapon was a stone, and the killer is a tall, left-handed man who limps, smokes Indian cigars with a holder, and wears specific boots, a grey cloak, and has a blunt penknife. Back at the hotel, Holmes explains his deductions to Watson: 'Koo' was an Australian signal, and McCarthy's dying word 'rat' was actually 'Ballarat', both pointing to an Australian connection. The killer is thus an Australian from Ballarat. Through his inquiries, Holmes deduces that Mr. John Turner, Alice's father, fits the description of the murderer. Turner arrives, gravely ill, and confesses that he knew McCarthy from his past as a 'bushranger' named 'Black Jack of Ballarat' in Australia. McCarthy blackmailed Turner for years, threatening to reveal his criminal past, and pushing for his son to marry Alice. Turner killed McCarthy in a fit of rage after overhearing McCarthy's crude remarks about Alice.