After the human exploration ship Bascom Hall crash-landed on the Hspa Nki's homeworld, the aliens allowed the survivors to settle on a high plateau with air too thin for the aliens—but just right for humans. For decades, the two races lived apart but at peace.
When a ship from Earth blazed through the skies, the Hspa Nki journeyed up to the plateau and demanded a retroactive land tax the settlers could not pay. But the aliens took a keen interest when they saw settlers playing ultimate flying disc, and the aliens loved to gamble. They offered to cancel the tax—if the settlers could beat them at the game.
Now, Connor and a team from the settlement journey to the thick air of the planet's lowlands, into a crowded alien city, with one mission: win or go "home"—to an Earth the young team had never seen.