We were crossing a ridge when Corgan was lifted off the ground by something. "Shoot it! Shoot the tyrannosaur!" he screamed as blood streamed from the puncture wounds that had opened up in belly. I fired into the empty space above him to no effect. Then Corgan's ragged corpse dropped to the forest floor, and I was alone. Utterly alone. There was no dinosaur. There was nothing.
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.