Beginning of the end

When a fatal plague hits camelot, a plague caused by powerful dark magic. Arthur and his most trusted allies, Merlin, gwaine, Leon, Percival,elyan and lancelot set out on a dangerous quest to find the source of the plague and put an end to the people's suffering. When merlin discovers the only way to save camelot is to use his life force, his magic to counteract the dark magic; how far will he go to save the people he loves? and what will his friends do if they find out who Merlin really is?