From the back of the book. You and a group of your friends are on an expedition across some particularly treacherous moonscape. A sudden quake rocks the mountain, and you and your leader are separated from the group. It's summer vacation - not that that means a lot; there aren't really seasons here on the moon. What it does mean is that you're making big plans. You'll have a lot of expeditions to choose from, but just remember: much of the moon is uncharted territory. Don't get lost - and don't run too low on your oxygen tank!"