The narrator, Charles Darnaway, a recent graduate of the University of Edinburgh, travels to the remote island of Aros off the northwest coast of Scotland.
Charles has come in search of sunken treasure, as he believes a ship of the Spanish Armada sank in the bay under his uncle's home long before.
Charles is surprised to find Rorie and Gordon anxious and full of foreboding, though both furtively evade his questions.
His cousin Mary Ellen confirms that a ship was recently cast away nearby, having been driven by a storm into the dreadful breakers around the promontory, breakers that roar a hundred feet high around the rocks and are called "the Merry Men" due to the vast noise they make, like shrieking laughter.
As he makes for the surface his handhold breaks off in his grip; when he pulls himself on shore he looks at it and is horrified to recognize a human leg bone.
Driven mad, Gordon flees into the storm and eventually flings himself into the sea, pursued by the silent stranger; both are swallowed up by the Merry Men.
I put a whole family there, in one of my tales; and later on, threw upon its shores, and condemned to several days of rain and shellfish on its tumbled boulders, the hero of another.
There was a long tradition in Scotland that the Devil appeared as a black man (Stevenson mentions this in a footnote to Thrawn Janet, another story in the same collection.)