Adrian Nightrunner, Warder at the time that the Caern was breached in the fall of 1994, returned with a fetish designed to strengthen the Caern's defenses. The fetish came in the form of a silver wire 'thread' that was laid in the Umbra, encompassing the perimeter of the Medicine Circle that made up the Wheel. This fetish attracted Lunes, which is why they have always been so plentiful around the Wheel. These Lunes provided an extra layer of protection against Umbral attacks. When the caern was transformed, this silver thread was lost, as far as is known right now. It is unknown if the fetish was broken or moved, or if it is still buried somewhere in the strangely transformed earth of the caern, still doing its job. The latter is generally not believed, but the truth has yet to be discovered.