In your enquiries as to the location of Fortress Bizzletinks, you discover that Lord Bizzletinks the Second had the drawbridge and all the walls covered with whoopie cushions and large piles of precariously-balanced chinaware, effectively making it impossible to sneak into. However, you've heard that the Mutant Owl People of Grul'ghast have a sacred nectar that will allow you to sprout your own soft feathery wings, and those wings, while not strong enough to carry you to great heights, will allow you to silently fly over the walls of the keep.