While assisting Holmes in an embezzlement case in Falmouth, Watson is called to aid Mrs. Ranstead, the survivor of a shipwreck. She and crewman Cluney were the only survivors from a ship that was transporting an ancient meteorite from St. John's to Falmouth.
Holmes and Watson attend the official enquiry, and Holmes seems taken with a rope burn on Cluney's jacket. He sends the local constable out on an errand, and the next day they mount watch on a buoy he has located. As they wait Watson spots a rowing boat heading toward it, and the truth of the matter is made clear.