On the Edges of Elfland. David Mosley

Alfred Perkins was an ordinary young man who grew up in the small English village of Carlisle. When he was a boy his godfather, old Oliver Cyning, used to tell him stories about Elfland, the place where all the fairies, elves, gnomes, goblins, and more lived. Alfred grew up believing in those stories. One day, Mr. Cyning told Alfred they had to stop spending time together. Eventually, Alfred stopped believing. Now Alfred has returned home from university and has made the startling discovery that his godfather had not lied to him and that now his fate, along with that of the village, was tied to that of Elfland and it was Alfred's job to save them both.