As mentioned above, I am looking for a fic where arthur is a wolf and merlin is his mate. The story begins as arthur and his knights visiting ealdor for some sort of ceremony where they select mates. I know a mask plays a main role in this story. Initially it's nimueh who wears the mask that is meant to be the other half of the mask arthur is wearing, however at the last minute she puts the mask on merlin instead. A reluctant merlin runs away only to be chased by arthur, and merlin submits to him in the end.
I know my summary is vague, but if anyone happens to know this story it would be very helpful.