The village of Glen Cairn was situated in a valley in the broken country lying to the west of the Pentland Hills, some fifteen miles north of the town of Lanark, and the country around it was wild and picturesque. The villagers for the most part knew little of the world beyond their own valley, although a few had occasionally paid visits to Glasgow, which lay as far to the west as Lanark was distant to the south. On a spur jutting out from the side of the hill stood Glen Cairn Castle, whose master the villagers had for generations regarded as their lord.