Keep of the Ancient King

From the Face-page: You are Amy. Your horse, Acorn, has been stolen by the evil Shadow Rider. When the Good Knight of the Golden Dragon and his warriors pass your father's inn on their way to the KEEP OF THE ANCIENT KING, you volunteer to lead them. Maybe you'll find your horse there. From the back of the book: Will you be attacked by fierce monsters? Will you be trapped by an evil wizard's magic spell? Or can you outsmart them all? Turn the page and find out! Only you can decide where your adventure will lead. From TSR, Inc., the producers of the Dungeons and Dragons game.