(Inside are a notepad and a small silver device that looks like a wheel.)

(On the notepad is a list of Atreian treasures and where to find them. Some of these items have an X marked next to them.)

(There is a fresh mark next to Silver Blade Rotan. It's safe to assume that the small wheel is related to this treasure.)

(You take the Rotan Summoning Object from the grave robber's bag and put it in your cube.)