Lured from the property by a mysterious phone call, he is found dead on the moor, having succumbed to a heart attack from fear.

Also staying at the castle is a distant relative of the Baskervilles, Lady Beryl Vendeleure, who originally intended to sell her land and moor to the late Lord.

In order not to let Henry Baskerville become another victim of the ghost dog, executor Dr. Mortimer, family doctor and friend of old Lord Charles, asks the London master detective Sherlock Holmes for help.

As a first measure, Holmes sends his faithful companion Dr. Watson to Baskerville Castle to keep a close eye on what is happening.

Have the events been orchestrated by the secretive house servant Barrymore, who has been seen returning light signals coming from the moor at night?