Dr James Mortimer calls on Sherlock Holmes in London for advice after his friend Sir Charles Baskerville was found dead in the yew alley of his manor on Dartmoor in Devon.

The death was attributed to a heart attack, but according to Mortimer, Sir Charles's face retained an expression of horror, and not far from the corpse the footprints of a gigantic hound were clearly visible.

According to an old legend, a curse runs in the Baskerville family since the time of the English Civil War, when a Hugo Baskerville abducted and caused the death of a maiden on the moor, only to be killed in turn by a huge demonic hound.

Allegedly the same creature has been haunting the manor ever since, causing the premature death of many Baskerville heirs.

Sir Charles believed in the plague of the hound and so does Mortimer, who now fears for the next in line, Sir Henry Baskerville.