Mystic's Vale in Heroes 5

Hidden, forgotten, lost - somewhere in this world there is an ancient city that holds the secret to immortality, a secret that will be revealed only to the hero that reigns from atop its towers. At least, so the legend says... It used to be that only the most superstitious and gullible believed, but now there is a rumour that the town has been found. Mighty rulers of neighbouring lands scoff openly at the stories, while in secret they are all sending small, powerful detachments to seek out the truth of these tales. After all, this is a bet that is worth hedging.