The show begins with the lecherous Sir Hugo Baskerville, who became the victim of a terrifying hound, as he chased a young girl over a deserted moor. Ever since, every generation of Baskervilles has been tormented by a mysterious and supernatural hound from Hell. The recent death of Sir Charles Baskerville has raised these ancient fears.

Sir Henry, Charles’s nephew and only heir, has come back from Canada to England to claim his inheritance. This includes the eerie Baskerville Hall and its surrounding wild Devonshire moors. Henry asks Sherlock Holmes to solve the mystery surrounding his Uncle Charles’s death.

Whilst in London, Sir Henry gets an anonymous note warning him not to go to Baskerville Hall. Also, a bearded man follows him, and strangely, one of his shoes is stolen.

Holmes says that he is too busy in London to accompany Sir Henry to Devonshire, and he sends Dr. Watson to be his eyes and ears, asking him to report back regularly. In Devonshire, Watson gathers clues and writes reports to Holmes, who is supposed to be in London. He discovers guards looking for an escaped convict roaming the moors. He meets potential suspects - Mr. and Mrs. Barrymore, the Baskerville’s servants, and Jack Stapleton and his very attractive sister, Beryl.

Watson observes and picks up clues. He sees Mr. Barrymore lurking around the mansion at night. Watson also notices a lonely figure keeping watch over the moors and he hears the sounds of a dog howling. Beryl Stapleton gives an enigmatic warning and Watson learns of a secret encounter between Sir Charles and a local woman named Laura Lyons on the night of his death.Watson discovers that Mr. Barrymore’s suspicious activity is his attempt to aid the escaped convict on the moor, who is actually his wife’s brother. The doctor interviews Laura Lyons, and discovers that she did indeed know Sir Charles and had arranged to meet him on the night of his death. Watson also finds out that the lonely figure on the moors is none other than Sherlock Holmes himself. Watson has done well, but it is Holmes who solves the mystery.

Mr. Stapleton, Holmes has discovered, is actually a Baskerville, and next in line to inherit the Baskerville house and fortune. He is the prime suspect. Laura Lyons was only a pawn in Stapleton’s game, who lured Charles onto the moor. Stapleton then set his ferocious pet dog on Sir Charles and the fright gave him a heart attack.

In a dramatic final scene, Stapleton lures Sir Henry to his house at night, and when Henry is walking home across the foggy moors, he sets his mad-dog after him. Holmes shoots the dog just in time and chases Stapleton into a quicksand, where he sinks to his death. Beryl Stapleton, who turns out to be Stapleton’s wife and not his sister, is discovered tied up in his house.

Back in London, Holmes explains that Stapleton was the bearded man who followed Henry through London, and the stolen shoe was used to give the hound Henry’s scent. The mysterious warning note came from Beryl Stapleton, whose husband had denied their marriage so as to seduce and use Laura Lyons.