On sick leave from Scotland Yard, Inspector Alan Grant is planning a quiet holiday with an old school chum to recover from overwork and mental fatigue. Traveling on the night train to Scotland, however, Grant stumbles upon a dead man and a cryptic poem about "the stones that walk" and "the singing sands," which send him off on a fascinating search into the verse's meaning and the identity of the deceased. Despite his doctor's orders, Grant needs just this sort of casual inquiry to quiet his jangling nerves.