Penhaligon takes on pirates and sea serpents on the high seas. The creatures of Porthleven are suffering from a mysterious illness that looks like Febra lupi, the curse of the Romany wolves, which has no known cure. The dashing apothecary fox Penhaligon must find a cure or risk losing everyone he holds dear! Penhaligon uncovers a fragment of parchment that just might be a recipe for a cure—and it includes ingredients found only on the haunted Howling Island. But the obstacles Penhaligon must face on his quest for the cure make ghosts seem friendly: Pirates! Sea serpents! Double-crossing ferrets! Can Penhaligon make it back in time to save his village?