there. Holmes coldly refuses to tell him. Roylott becomes further enraged. The following excerpt is intended to establish that the conflict is between Sherlock Holmes and Dr. Roylott.

“I will go when I have said my say. Don't you dare to meddle with my affairs. I know that Miss Stoner has been here. I traced her! I am a dangerous man to fall foul of! See here.” He stepped swiftly forward, seized the poker, and bent it into a curve with his huge brown hands.

“See that you keep yourself out of my grip,” he snarled, and hurling the twisted poker into the fireplace he strode out of the room.

Disregarding Roylott's warning, Holmes, accompanied by Watson, goes down to Stoke Moran that very afternoon. He examines Helen's bedroom and Dr. Roylott's bedroom next door. He sees enough to satisfy him that Roylott is trying to kill Helen to prevent her from getting married, in which case he would have to pay his stepdaughter a substantial annual sum from her mother's estate. Holmes and Watson spend the night in Helen's bedroom. When they hear the low whistle at three o'clock in the morning, Holmes strikes a light and sees the "speckled band," which is a deadly poisonous snake trained by Roylott to crawl through the ventilator and down onto the bed. This was obviously the way Roylott killed Helen's twin sister Julia two years ago when she occupied this room. Holmes drives the snake back up the bell-pull and through the ventilator. The angered snake bites Dr. Roylott, and Holmes and Watson find him dead.

Thus the conflict between Holmes and Roylott, man-versus-man, is resolved when Holmes kills Roylott with his own poisonous snake. At the very end of the story the author, Arthur Conan Doyle, uses the following comments by Holmes to show that the conflict in "The Adventure of the Speckled Band" was indeed between Holmes and Dr. Grimesby Roylott. Roylott wanted to kill Helen; Holmes wanted to protect her. Holmes tells Watson:

"Some of the blows of my cane came home and roused its snakish temper, so that it flew upon the first person it saw. In this way I am no doubt indirectly responsible for Dr. Grimesby Roylott's death, and I cannot say that it is likely to weigh very heavily upon my conscience.”

The author Sir Arthur Conan Doyle sets up the story in such a way that the conflict becomes one between Sherlock Holmes and Dr. Grimesby Roylott. When Roylott is killed by his own snake at the end of the story, that resolves the conflict. Holmes even tells Watson:

"Some of the blows of my cane came home and roused its snakish temper, so that it flew upon the first person it saw. In this way I am no doubt indirectly responsible for Dr. Grimesby Roylott's death, and I cannot say that it is likely to weigh very heavily upon my conscience.”

Helen Stoner comes to Sherlock Holmes early in the morning. She tells him a long tale about her family and about her sister Julia's mysterious death two years ago. She is fearing for her own life now because she has heard the same low whistle which Julia told her about shortly before she died an agonizing death. After Holmes promises to offer his advice and assistance, Helen leaves. Her violent, ill-tempered stepfather has been following her. He bursts into Holmes and Watson's sitting room unannounced and threatens Holmes with violence if he interferes in his affairs.

“I will go when I have said my say. Don't you dare to meddle with my affairs. I know that Miss Stoner has been here. I traced her! I am a dangerous man to fall foul of! See here.” He stepped swiftly forward, seized the poker, and bent it into a curve with his huge brown hands.

“See that you keep yourself out of my grip,” he snarled, and hurling the twisted poker into the fireplace he strode out of the room.

This is the only time Dr. Roylott appears in person and alive, but his presence haunts the rest of the story. When Holmes and Watson go down to Stoke Moran to examine the bedrooms, the reader always feels a danger that Roylott might return unexpectedly and become infuriated to find the detective inside his house after warning him not to meddle with his affairs. No doubt the country manor would contain several guns used for hunting, and Roylott seems quite capable of trying to commit murder.

After Conan Doyle introduces Dr. Roylott in person at 221B Baker Street, he has established that the conflict is between Holmes and Roylott. There is no other significant conflict in the story, and it is this battle of wits between the two cunning men that makes "The Adventure of the Speckled Band" so dramatic. The conflict is over Helen Stoner. Simply put, Dr. Roylott wants to kill her and Holmes wants to protect her. She is what is often called the MacGuffin in Hollywood parlance. She is the "bone of contention," what the conflict is about. There cannot be a serious and prolonged conflict in a story unless the conflict is about something specific. 

When Miss Helen Stoner comes to visit Sherlock Holmes, she tells him about her sister Julia's mysterious death two years ago. Her sister's dying words were “The speckled band!”

Miss Stoner cannot understand what these words mean. However, they are, she believes, the key to what happened to her sister, whom she strongly believes was murdered by their stepfather, Dr. Roylott. She fears Roylott is now trying to murder her. Holmes agrees with her and sets out to find speckled band that killed her sister. The story is called "The Adventure of the Speckled Band" because a speckled band is the murder weapon.

Because Roylott allows a band of Gypsies to live on the property at Stoke Moran, Holmes at first thinks the term "speckled band" refers to them. As he admits at the end, this supposition confused him at first, leading him in the wrong direction. Not until he and Watson hide in Miss Stoner's room and see the snake slither down the bell pull does Holmes put two and two together and realize that the "speckled band" that killed Miss Stoner's sister was a poisonous snake.

As he often does in his mysteries, Doyle has added a touch of the exotic and "Oriental" to his story: Gypsies (who were thought by the English to be of Egyptian descent and hence "Oriental"), a cheetah and baboon from India that wander the grounds, and Dr. Roylott's background as a doctor who worked in Calcutta and beat his Indian servant to death in a fit of rage. Whatever murdered the pure and wholly English Stoner sisters, it reflects the sense of an outside "pollutant" coming into England.

"The Adventure of the Speckled Band" is an example of a sub-genre of mystery stories commonly called a "Locked Room Murder Mystery." Julia was in her bedroom when she experienced the pains and psychological trauma that resulted in her death. Her door had been locked and the windows were covered with heavy iron shutters bolted on the inside. Julia and Helen both locked themselves inside their rooms at night because of their fear of the cheetah and baboon. In a Locked Room Murder Mystery the question is not so much whodunit? as how was it done?

There have been countless locked-room mystery novels and short stories published over the years. The prototype is undoubtedly "The Murders in the Rue Morgue" by Edgar Allan Poe. The following excerpt from a newspaper article quoted in that story describes the locked-room at the Rue Morgue where two women were horribly murdered.

“Four of the above-named witnesses, being recalled, deposed that the door of the chamber in which was found the body of Mademoiselle L. was locked on the inside when the party reached it....Upon forcing the door no person was seen. The windows, both of the back and front room, were down and firmly fastened from within....There was not an inch of any portion of the house which was not carefully searched. Sweeps were sent up and down the chimneys....A trap-door on the roof was nailed down very securely—did not appear to have been opened for years. 

In both stories the identification of the perpetrator becomes relatively easy after the detective figures out how it was possible to kill anyone who was securely locked inside a room. In the case of "The Adventure of the Speckled Band," Sherlock Holmes deduces that Dr. Roylott sent a poisonous snake through a ventilator, knowing that eventually it would bite Julia in her bed. In the case of "The Murders in the Rue Morgue," C. Auguste Dupin realizes that there must have been a way for the perpetrator to get inside the locked room, regardless of how thoroughly the police have searched the premises. It turns out that one of the windows was not firmly shut but only appeared to be so.

The theme of "The Adventure of the Speckled Band" can be called "a locked-room murder mystery."

Arthur Conan Doyle has Sherlock Holmes himself state the theme of the story at the moment Holmes and Watson enter Dr. Roylott's bedroom and find him dead.

"It is a swamp adder!" cried Holmes; "the deadliest snake in India. He has died within seconds of being bitten. Violence does, in truth, recoil upon the violent, and the schemer falls into the pit which he digs for another."

Holmes could not have known that by striking the snake and driving it back up the bell-rope and through the ventilator into Dr. Roylott's room he would be causing Roylott's death. This is understandable because, although Holmes seems to have some knowledge about that particular kind of snake, he did not know it be angry enough to bite its owner when it returned to his room. Neither did Dr. Roylott, apparently. He was not prepared from the snake's sudden return and did not have his noose ready to capture it.

Did Dr. Roylott expect Sherlock Holmes to arrive at Stoke Moran to interfere with his nefarious plans for his stepdaughter? Probably not. He may have thought that Holmes would not be sufficiently interested in Helen's distress to travel down there in person, since there was no fee to be gained. He may have thought that he had intimidated Holmes by twisting the iron polka and threatening him. And he felt somewhat protected by the cheetah and the baboon. At any rate, he didn't suspect that Sherlock Holmes was in the bedroom right next door to his own. It was poetic justice that he was killed by the snake he had used to kill Julia and was attempting to use to kill Helen.

Holmes' quotation is referring to Psalm 7:16 in the Old Testament. "His mischief shall return upon his own head, and his violent dealing shall come down upon his own pate."

In “The Adventures of the Speckled Band” the theme of the story is that evil will be punished by fate if not by man's instruments of justice.

The story demonstrates a kind of karma.  The doctor commits evil deeds, and those deeds pave the way for him to destroy himself.  He trains the snake to be his instrument of death, and the snake returns to him to kill him.

Holmes comments that a doctor who harms people is dangerous not just because he violates the Hippocratic Oath to do no harm.

When a doctor does go wrong he is the first of criminals. He has nerve and he has knowledge. (enotes pdf text p. 17)

The mystery centers on how Sir Grimesby Roylott, a dotor, manages to commit murder without anyone suspecting.  Holmes determines that he has used his reputation for eccentricity, and his animal collection, to accomplish this.  He trains a snake to do the murders for him.  Yet it is also the training of the snake that causes his demise, because Holmes attacks the sake and sends it back to him.

Some of the blows of my cane came home and roused its snakish temper, so that it flew upon the first person it saw. (p. 20)

Roylott would not have been killed if he had not trained the snake to do his dirty work.  He was punished by fate, karma, or his own evil.  In the end, he got what he deserved, and Holmes did not really have to play a part in it.

There is a simple theme in this story, good vs evil.  Dr. Grimbsy Roylott represents evil and Sherlock Holmes is a force for good.  If you wanted to characterize it more dramatically, you could say that it is a story about chivalry, where Sherlock Holmes is the white knight rescuing the damsel in distress, Helen Stoner from the evil clutches of the dark lord, Dr. Grimbsy Roylott.

Holmes emerges as a hero, slays the dragon (Roylott), rescues the girl and solves the mystery.

Another theme that emerges in this story is one of chaos, which is depicted by the decayed house and Dr. Roylott's behavior, particularly when he threatens Holmes with physical harm if he gets involved with Helen Stoner's case.  As contrasted with the world of Helen Stoner, who is engaged to be married and trying to live a traditional, normal life.

Roylott is trying to disrupt Helen's life, he wants to kill her so that he can hide his behavior and keep her money for himself.

The identity of the culprit is Dr. Grimesby Roylott. He is strongly suspected from the beginning because, for one thing, he had an obvious motive for killing Julia Stoner two years ago and he has the same motive for trying to kill Helen Stoner now. Under the terms of his deceased wife's will, Roylott would be forced to turn over one-third of his dwindling capital to either stepdaughter if she got married. So he wants to kill the girls when they become engaged, and, being a doctor and a scientist, he knows how to do it without getting caught. Helen's life has only become endangered recently because, as she tells Sherlock Holmes at their initial meeting:

"A month ago, however, a dear friend, whom I have known for many years, has done me the honour to ask my hand in marriage. His name is Armitage—Percy Armitage—the second son of Mr. Armitage, of Crane Water, near Reading." 

Roylott might be able to intimidate his stepdaughters and refuse to give them any part of their mother's bequest. However, he knows that if one of the girls got married he would have to deal with her husband. In those Victorian times most women knew little about practical matters and their husbands took charge of such things. Roylott is iron-bound by law to part with his capital if either girl marries.

Helen describes her stepfather as a powerful and violent man. And he proves this when he storms into Holmes' and Watson's rooms to demand to know what Helen has been telling them. He says:

"I am a dangerous man to fall foul of! See here.” He stepped swiftly forward, seized the poker, and bent it into a curve with his huge brown hands."

Although Helen does not suspect her stepfather of trying to murder her, Holmes feels sure that Roylott was somehow connected with Julia Stoner's death and may be connected with a plot to murder Helen. The presence of a band of gypsies on the grounds at Stoke Moran misleads Holmes, and is intended by the author to mislead the reader. Holmes thinks that Helen's dying reference to a "speckled band" may refer to a band of gypsies wearing speckled head bands, or something of the sort. Dr. Roylott does not reappear in the story until after he found dead in his room with the "speckled band" wrapped around his head; but his threat of violence hangs like a cloud over the rest of the story. The reader half-expects Dr. Roylott to return home from London unexpectedly and perhaps trying to kill Holmes and Watson with one of his hunting guns. Watson has brought his revolver; there could be a shootout. Helen has told the detective that her stepfather planned to stay in London all that day; but it seems possible that he might become suspicious of both Helen and Holmes and return to Stoke Moran much earlier than anticipated.

Since Dr. Roylott is killed by his own poisonous snake, there is no need to bring in the police. Helen wants the matter hushed up anyway. The doctor's death is attributed to his being bitten while handling his snake, which was one of the many exotic animals he studied. Helen will inherit the house and all the money, and she will be able to go ahead with her wedding to Percy Armitage.

To get a great deal of information about Sir Arthur Conan Doyle’s “The Adventure of the Spotted Band,” follow the links to the right of this question.  This can help you with any questions you may have about the story.  The quick answer to your question is that the villain is Dr. Grimesby Roylott, who is the stepfather of Helen Stoner, the young woman who comes to Sherlock Holmes for help.

In this story, Roylott married Helen’s mother some years before.  Helen had had an older sister but that sister died in mysterious circumstances not long before she was going to be married.  Now Helen is engaged and there are mysterious things happening around the estate where she lives with her stepfather.  Her mother died eight years before the events of this story.

At the end of the story, we find that Roylott is the villain.  He wanted to kill his stepchildren because, if he did so, he would not lose any of the money that his wife had bequeathed to them.  Thus, the motive for his attempted murder of Helen (and, we presume, of his actual murder of her sister) was Roylott’s desire for money.

A case could be made that it is Dr. Roylott who is the protagonist in "The Adventure of the Speckled Band." That would make Sherlock Holmes the antagonist in the drama. Here is a definition of the term "protagonist" by Lajos Egri in his invaluable book The Art of Dramatic Writing. 

The pivotal character is the protagonist. According to Webster’s dictionary, the protagonist is “one who takes the lead in any movement or cause.”

Anyone who opposes the protagonist is an opponent or antagonist.

As we see, a pivotal character never becomes a pivotal character because he wants to. He is really forced by circumstances within him and outside of him to become what he is.

The protagonist is the character who starts the action, who makes the story happen, and who is mainly responsible for its continuation. Dr. Roylott started the whole story two years earlier when he killed Julia. We do not know that for sure, but it is not necessary to know the identity of a protagonist immediately or to know his motive. For example, there are many movies and television shows in which someone is committing a series of murders. No one knows who he is or why he is doing it, but that person is the protagonist and the investigator's problem is to expose him. As another example, in "The Hound of the Baskervilles" it is Mr. Stapleton who owns the hound and plans to murder Sir Henry Baskerville, but nobody knows that until near the end of the long story. 

If Dr. Roylott had only murdered Julia and had never given Helen cause to fear for her own life, then Dr. Roylott would not be the protagonist. But he now wants to kill Helen for the same reason he killed Julia. Helen wants to get married and Roylott will be forced to pay her one-third of his annual income. According to Egri, "a pivotal character never becomes a pivotal character because he wants to. He is really forced by circumstances within him and outside of him to become what he is." Dr. Roylott is being forced to try to murder Helen because Helen is engaged to be married. His income has already shrunk drastically. His big house is heavily mortgaged. He would be ruined if he had to pay Helen 250 pounds a year out of his total annual income of 750 pounds. He murdered Julia for the same reason he intends to murder Helen. 

Arthur Conan Doyle introduces Dr. Roylott early in the story by having this violent man come directly to Baker Street and threaten Sherlock Holmes. His intrusion and his threats of bodily harm are proof of his strong motivation. He undoubtedly knows that Holmes suspects him of killing Julia as well as of having sinister plans against Helen, but Roylott is half insane and doesn't care what Holmes thinks as long as he can't prove it. And he hopes to keep Holmes from proving it by trying to frighten the detective into dropping out of the investigation and staying away from Stoke Moran. Holmes is a worthy antagonist to this protagonist. Holmes is working for Helen Stoner for nothing, but that doesn't stop him from pursuing his investigation until the problem created by Dr. Roylott is solved.

Two of the main characters are, of course, Sherlock Holmes and Dr. Watson. Sherlock Holmes is a brilliant and highly logical detective, who shows his caring and compassionate side in this story, while Dr. Watson, the story's narrator, is his faithful and less uniquely brilliant sidekick. The other main characters are Helen Stoner and Dr. Grimesby Roylott, her stepfather. Helen Stoner is the good-hearted but badly frightened woman who comes to Holmes for help. She is engaged to be married and is fearful that her stepfather is going to kill her. Even though she can't pay for his services, Holmes feels enough sympathy for her that he takes on her case.

Dr. Roylott is an ill-tempered man whose family estate has fallen on hard times. He had to go to India to earn money but has now returned. He arrives at Holmes's office and in a display of bad temper tells him to stay away from his stepdaughter. He bends one of Holmes's fireplace pokers as a show of strength. Neighbors avoid visiting his estate because of his bad temper and because he lets a cheetah roam his grounds.

Dr. Grimesby Roylott is considered to be the main antagonist of Arthur Conan Doyle's short story "The Adventure of the Speckled Band." Like most of Doyle's antagonists, Dr. Roylott is the classic villain of the story—he's violent and aggressive, vain, greedy, antisocial, and antipathic, and most importantly, he's the culprit, or in this case, the murderer.

Dr. Roylott is the last descendant of an aristocratic but impoverished family, and judging by his actions, his main goal in life is to have financial stability. For this reason, he becomes a doctor, sets up a practice in India, and marries a wealthy widow of an Indian Major-General who has two daughters from her previous marriage—Helen and Julia.

Unfortunately, his wife, Mrs. Stoner, tragically loses her life in a train accident, and Dr. Roylott takes his stepdaughters to live with him in his family's old home in England (Stoke Moran). There, the people dislike and even fear him, because he has a very intimidating and threatening aura and he's cruel, unkind, and selfish, which only further accentuates his antagonistic nature.

In her will, Mrs. Stoner leaves all of her wealth to her husband, but she also makes a special note that when her daughters decide to marry, a portion of the inheritance will go to them and they can claim an income of £250. Thus, when Julia is engaged to be married, Roylott realizes that he will lose a significant share of the fortune, and in true villain fashion, he hatches a nefarious plan to murder his stepdaughter before she's married. Roylott trains a swamp adder (the deadliest Indian snake) to enter Julia's room and bite her. His plan is successful, and Julia becomes his second victim, as he previously beat his butler to death when his home in Calcutta was robbed.

When Helen becomes engaged to be married as well, she decides to ask Sherlock Holmes to investigate the mysterious circumstances surrounding her sister's death. Naturally, Holmes solves Julia's murder and manages to save Helen of the same fate, as Roylott plotted to kill her as well, in order to keep his wealth.

All of Roylott's actions and thoughts indicate that he's the main antagonist of the story, not only because he's the main opponent of the protagonist, but also because he's also a truly evil man. Holmes even remarks that Roylott's death is justified to some degree, because he got what he deserved in the end.

Sherlock Holmes is usually considered the protagonist in any of his stories. Helen Stoner comes to him for help because she fears her life is in danger. The prime suspect is her stepfather Dr. Grimesby Roylott. The author, Sir Arthur Conan Doyle, has Dr. Roylott put in an appearance at 221B Baker Street shortly after Helen leaves. This meeting between Holmes and Roylott is necessary to establish that Dr. Roylott is Holmes' opponent, or the antagonist. The violent and half-mad Roylott establishes the conflict during his short appearance at Holmes' residence.

“I will go when I have said my say. Don't you dare to meddle with my affairs. I know that Miss Stoner has been here. I traced her! I am a dangerous man to fall foul of! See here.” He stepped swiftly forward, seized the poker, and bent it into a curve with his huge brown hands.

Dr. Roylott does not appear in the story again until after he has been bitten by his own poisonous snake and is found sitting dead in his room. But his existence as a threat has been established, and it hovers like a black cloud over Stoke Moran. He seems fully capable of killing Holmes and Watson if he found them snooping around inside his house. No doubt he would have a number of guns to choose from on a country estate. When his body is discovered it shows that Holmes has been victorious in their conflict. In the very last paragraph of the story he accepts responsibility for Roylott's death.

"Some of the blows of my cane came home and roused its snakish temper, so that it flew upon the first person it saw. In this way I am no doubt indirectly responsible for Dr. Grimesby Roylott's death, and I cannot say that it is likely to weigh very heavily upon my conscience.”

There is only one protagonist and one antagonist. Dr. Watson accompanies Holmes because he is the narrator and has to observe everything from the first appearance of Helen Stoner at 221B Baker Street. But Holmes is the protagonist and Roylott the antagonist. Helen Stoner might be called "the bone of contention" or "the MacGuffin." 

The only person fulfilling the role of a detective in Sir Arthur Conan Doyle's "The Speckled Band" is his most famous character, Mr. Sherlock Holmes. Mr. Holmes is a consulting detective; that is, he does not work for the police or an agency. Instead, people come to him when they have a matter they want investigated. Sometimes, the police or other detectives (such as Inspector Lestrade) are involved in the case. In the story of "The Speckled Band," Mr. Holmes is the only detective and is accompanied by his companion Dr. Watson.

In this story, Miss Helen Stoner is seeking the help of Mr. Holmes and Dr. Watson. She has come to London in the wee hours of the  night from her family's estate in the countryside. She has been hearing some strange sounds in the night and fears her life may be at risk. Several years prior, her sister began hearing strange sounds in the night and died mysteriously. Mr. Holmes and Dr. Watson travel to Miss Stoner's estate and spend the night in her room, discovering that her stepfather has been trying to send a poisonous snake into her room to kill her!

There are four main characters in Sir Arthur Conan Doyle's short story "The Adventure of the Speckled Band."

Sherlock Holmes, the great detective, needs no introduction to modern readers, but since this was only the eighth short story featuring him, Holmes was still establishing himself as a character with the Victorian reading public. He is a brilliant consulting detective with a particular flair for deductive reasoning as well as formidable courage and a coldly logical attitude to his life and work.

Doctor Watson performs three main roles. He is the storyteller, he asks the questions the reader would ask, and he assists Holmes. Although a tradition quickly grew up in films and television adaptations of portraying Watson as stout, bumbling, and dim-witted, in the stories, he is an intelligent man and has the same physique as Holmes. He is more sympathetic and less logical in his approach to cases than the great detective.

Miss Helen Stoner is Holmes's client. She is a young woman who is still in mourning for her sister, who died two years before. She is terrified by the situation in which she finds herself, and her face is described as "all drawn and grey, with restless frightened eyes, like those of some hunted animal."

Dr. Grimesby Roylott is the stepfather of Miss Moran. He is a frightening man, of great physical strength with an extremely violent temper. His eccentric habits include keeping a menagerie of animals at his house, with a cheetah and a baboon that roam the grounds.

Sherlock Holmes calls himself a "consulting detective." Nowadays we might call him a private detective, a private eye, or even a shamus. He is strictly a non-professional, and as such he is limited as to the kinds of cases he can take on. Then as now the police do not want private detectives interfering with murder cases. Holmes is able to get involved in solving murders only because he has done innumerable favors for Scotland Yard detectives and has allowed them to take all the credit for solving many cases he has solved himself. But it should be noted that Holmes rarely gets involved in murder cases before the police have been summoned to the scene of the crime. In the best-known Sherlock Holmes tale "The Hound of the Baskervilles," for example, Holmes is not trying to solve a murder but to prevent a murder. This is strictly legitimate work for a private eye, and many of the Sherlock Holmes stories are about clients who are in danger of being killed but are not actually dead.

In "The Adventure of the Speckled Band," Helen Stoner comes to Holmes for advice. She thinks she might be in mortal danger and is terrified. Holmes goes down to Stoke Moran accompanied by Watson, not to investigate the two-year-old death of Julia Stoner, but to protect Helen. It is noteworthy that he does not even try to arrest Dr. Roylott when he discovers what the vicious man has been up to; instead, the author conveniently arranges for Roylott to be killed by his own snake. Holmes simply does not have the authority to make an arrest. He does not even make the truth about Roylott's swamp adder or about Julia Stoner's death publicly known. Dr. Watson explains in the opening paragraph that the whole thing has been kept secret until he is currently revealing the truth in this story he entitles "The Adventure of the Speckled Band."

It is possible that I might have placed them upon record before, but a promise of secrecy was made at the time, from which I have only been freed during the last month by the untimely death of the lady to whom the pledge was given. It is perhaps as well that the facts should now come to light, for I have reasons to know that there are widespread rumours as to the death of Dr. Grimesby Roylott which tend to make the matter even more terrible than the truth.

This case is told to Holmes by a woman named Helen Stoner. Holmes and Watson, invite her to share her problem. Miss Stoner tells them that when their mother died Helen and Julia were left in the custody of their stepfather, a dangerous Dr. Grimesby Roylott.  They lived in fear and misery, despite of the being wealthy because of money left by their mother.  Julia mysteriously died two weeks before her marriage, and before she dies she said to Helen the words ‘speckled band’, but Helen doesn’t have a clue as to the meaning.  After two years Helen got engaged, her stepfather approved of it. A renovation of their house forced Helen to sleep in Julia’s room and she heard a whistle.  She lit a lamp found nothing, stayed awake and in the morning came to Sherlock Holmes for help. After she told him all her concerns they agreed to meet at her house but she should keep it secret from her stepfather. But she did not know Dr. Roylott followed her and threatened Holmes to back off, after she had left. Worried of Helen’s safety Holmes and Watson came to Stoke Moran and examined the room of Julia and Dr. Roylott. And Holmes noticed some odd things. Holmes asked Helen to signal to him and Watson to come back when Dr. Roylott sleeps. She does this and in the end Holmes and Watson solve the mystery.

There are several major characters in Sir Arthur Conan Doyle's Adventure of the Speckled Band, including Mr. Sherlock Holmes, Dr. John Watson, Miss Helen Stoner, and Dr. Grimesby Roylott. I would argue that Miss Helen Stoner is the most important of these characters, because she is the one who sets the plot in motion. Miss Stoner comes to Mr. Holmes' apartment in the wee hours of the morning from her countryside home. She fears that her life may be threatened, though she does  not say aloud that she thinks her stepfather is trying to kill her. Several years prior, Miss Stoner's sister was engaged to be married when she died in mysterious circumstances. Now, Helen is also engaged to be married and is sleeping in her sister's room while some work is being done on her own. When Helen hears strange sounds in the night just like those her sister mentioned before she died, she knows that she needs to seek help.