The left leg
It's a winter day in Dalton (a New England town near Boston) and Leonidas Witherall, "the man who looks like Shakespeare", is stepping off a bus after having been accused of bothering a beautiful young woman in a scarlet wimple (who promptly becomes known as the Scarlet Wimpernel). He takes refuge in a hardware store run by a former student, Lincoln Potter. Potter is inclined to be helpful, until the Wimpernel's purse is discovered in Witherall's pocket and Witherall is incautious enough to admit that he saw Potter's cash register being emptied by a man in a green satin suit carrying a small harp. He heads for the home of a former teaching colleague, Marcus Meredith, and finds him murdered—and missing his artificial left leg. Potter is enlisted by Witherall for help in solving the murder, along with intrepid housewife Topsey Beaton. Together they deceive an entire rummage sale, enlist the Scarlet Wimpernel to play a role, find the man in green satin, locate the left leg, and solve the murder.