A fiendish evil lurks beneath the mist-shrouded cliffs of England's fabled moors. In the form of a hellish hound, it feeds upon the trembling flesh of the heirs of Baskerville Hall. But before this savage beast can sink its teeth into the newest lord of the manor, it must pit its vicious fangs against the searing intellect of the most powerful foe it has ever encountered - the incomparable Sherlock Holmes (Peter Cushing) and Dr. Watson (Andre Morell).