Ghostly flaming apparition of a blade, slayer of spectres and all that is ethereal, wielded by its durable hilt inlaid in gold, silver, ivory and white pearls. It can turn the tide when fighting the intangible.
It looks like a cook's book. It is a cook's book. It is also where the cook, who happened to be a master spy, encoded all his secrets and contacts. The book has innocently fallen into your group's hands. Everyone wants it, and many are not subtle or peaceful in their attempts.