Yay, I love this story. I don't even object to its length, although I won't vow not to skip bits. "Amy" went by another name in the olden days, as I recall. I'll try to get back before this conversation disappears. I truly believe that "undercover" has been underused in X-fic. It's been used, all right, but seldom by really good writers. The device adds tension to the sexual tension that already exists. Which is good.