Belius and his gang of weasels steal a treasure map from captain Tonga, a boar serving in the king's guard in the land of Unger, and set off for Zanimos. On their journey they capture Montagu Frazzelbach (Monty), a proud and self important pig. Tonga pursues the weasels and joins forces with Rufus O'Malley, who with help from a seagull called Albert, and subtle clues left by Monty, eventually tracks down the weasels. In the final showdown an army of ruthless rats is mustered to fight alongside Belius, and the odds look in his favour; but then he has never encountered the magical brilliance of Rufus O'Malley........