The Glass Arrow

West Dorling is a quiet, remote village. So what brings three men to live thereabouts at practically the same time? None of them seems to pursue any professional employment, yet they live in some style. When a local learns their secret and threatens blackmail, the three meet to discuss the threat. But on arrival, two of them find the other lying dead, shot through the heart by a glass arrow. Before long a second has died in the same manner. Who is the mysterious archer and why use glass arrows?