Many generations ago, a spacecraft filled with evacuees fled from what used to be planet earth. En-route to their new home they were forced to crash land on a desolate desert planet. Immediately after landing they were attacked by an unknown beast in a misty dusty cloud. It is only by continually moving that they were able to survive. A large machine The Traveler was constructed from the remnants of their crashed spacecraft. It is in a constant state of reconstruction and addition, as it can never stop moving. When they do stop it is only long enough to pick up raw materials. The machine, several stories tall and several blocks wide became their only home. Many have lost their lives to build The Traveler and after forty years the population has grown to over 4000 people. Now unseen dangers await them at every turn and not all of them are on the planet.