The famous detective Sherlock Holmes and his friend, assistant Dr. Watson, examine a cane forgotten in an apartment on Backer Street by a visitor who came in their absence. Soon the master of the cane, doctor James Mortimer, appeared, a young tall man with close-set gray eyes and a long, sticking nose. Mortimer reads an old manuscript to Holmes and Watson - the legend of the terrible curse of the Baskervilles — entrusted to him not so long ago by his suddenly dead patient and friend Sir Charles Baskerville. Imperious and intelligent, not at all inclined to fantasies, Sir Charles took this legend seriously and was ready for the end that fate had prepared for him.

In ancient times, one of the ancestors of Charles Baskerville, the owner of the estate of Hugo, was unbridled and cruel. Inflamed with an unholy passion for the daughter of a farmer, Hugo abducted her. Having locked the girl in the upper chambers, Hugo and his friends sat down to feast. The unfortunate woman decided on a desperate act: she went down the ivy from the castle window and ran home through the swamps. Hugo rushed after her in pursuit of the dogs, his companions following him. On a wide lawn among the swamps, they saw the body of a fugitive, dead from fear. Nearby lay the corpse of Hugo, and above it stood a vile monster, similar to a dog, but much larger. The monster tormented the throat of Hugo Baskerville and sparkled with burning eyes. And although the writer of the legend hoped that providence would not punish the innocent, he still warned his descendants to beware of “going out into the swamps at night.

James Mortimer tells us that Sir Charles was found dead in a yew alley, not far from the gate leading to the swamps. And nearby, the doctor noticed fresh and clear traces ... of a huge dog. Mortimer asks Holmes for advice, as the estate’s heir, Sir Henry Baskerville, comes from America. The day after the arrival, Henry Baskerville, accompanied by Mortimer, visits Holmes. The adventures of Sir Henry began immediately upon arrival: firstly, his shoe was missing at the hotel, and secondly, he received an anonymous message warning “to stay away from peat bogs”. Nevertheless, he is determined to go to Baskerville Hall, and Holmes sends Dr. Watson with him. Holmes himself remains on business in London. Dr. Watson sends Holmes detailed accounts of life on the estate and tries not to leave Sir Henry alone, which soon becomes difficult, as Baskerville falls in love with Miss Stapleton, who lives nearby. Miss Stapleton lives in a swamp house with her entomologist brother and two servants, and her brother jealously guards her from the courtship of Sir Henry. Having set up a scandal over this, Stapleton then comes to Baskerville Hall with an apology and promises not to impede the love of Sir Henry and his sister, if within the next three months he agrees to be content with her friendship.

At night at the castle, Watson hears female sobs, and in the morning discovers the wife of the butler Barrymore weeping. Barrymore himself, he and Sir Henry manages to catch on the fact that he gives a candle at night out the window, and from the swamps he is answered the same. It turns out that a fugitive convict is hiding in the swamps - this is the younger brother of Barrymore's wife, who for her remained just a mischievous boy. The other day, he must go to South America. Sir Henry promises not to give Barrymore away and even gives him something from his clothes. As if in gratitude, Barrymore says that a piece of a half-burned letter to Sir Charles with a request to be "at the gate at ten o’clock in the evening" survived in the fireplace. The letter was signed by L. L. " In the neighborhood, in Kumb Tresi, there lives a lady with such initials - Laura Lyons. Watson goes to her the next day. Laura Lyons admits that she wanted to ask Sir Charles for money to divorce her husband, but at the last moment she received help “from other hands”. She was about to explain everything to Sir Charles the next day, but found out from the newspapers about his death.

On the way back, Watson decides to go into the swamps: even earlier, he noticed a man there (not a convict). Sneaking around, he goes to the stranger’s alleged home. To his great surprise, he finds a note scrawled in pencil in an empty hut: "Dr. Watson has left for Kumb Tresi." Watson decides to wait for the occupant of the hut. Finally he hears the approaching footsteps and cockes the revolver. Suddenly a familiar voice is heard: “Today is such a wonderful evening, dear Watson. Why sit in the stuffy? It's much nicer in the air. ” Friends barely have time to exchange information (Holmes knows that the woman that Stapleton gives out as his sister is his wife, moreover, he is sure that Stapleton is his opponent), when they hear a terrible scream. The scream repeats, Holmes and Watson rush to help and see the body ... of a runaway convict dressed in Sir Henry's costume. Stapleton appears. By clothes, he also takes the deceased for Sir Henry, then with a huge effort of will hides his disappointment.

The next day, Sir Henry leaves alone for a visit to Stapleton, and Holmes, Watson and detective Lestrade, who arrived from London, lie hidden in the swamps near their home. Holmes' plans are almost knocked down by the fog creeping from the side of the bog. Sir Henry leaves Stapleton and heads home. Stapleton launches a dog in his footsteps: a huge, black one, with burning mouth and eyes (they were smeared with a phosphorescent compound). Holmes manages to shoot the dog, although Sir Henry still survived a nervous shock. Perhaps even more shocking for him was the news that the woman he loved was Stapleton's wife. Holmes finds her bound in the back room - finally she rebelled and refused to help her husband in hunting for Sir Henry. She escorts the detectives into the depths of the quagmire, where Stapleton hid the dog, but no traces can be found. Obviously

To improve their health, Sir Henry and Dr. Mortimer embark on a trip around the world, and before sailing visit Holmes. After their departure, Holmes tells Watson the details of this case: Stapleton - a descendant of one of the branches of the Baskervilles (Holmes guessed this by his resemblance to the portrait of the wicked Hugo), he was often seen in fraud, but he managed to safely hide from justice. He was the man who invited Laura Lyons to first write to Sir Charles, and then forced her to refuse a date. Both she and Stapleton's wife were wholly in his power. But at a crucial moment, Stapleton's wife stopped obeying him.

Having finished the story, Holmes invites Watson to go to the opera - to the Huguenots.