Claus and Lavie are childhood friends whose fathers were also friends who died attempting to cross the "Grand Rapids." which is a mysterious and violent air channel that separates regions of the world. Not long after that happened Claus's mother passed away, and the two kids teach themselves how to fly their inherited "Vanship," eventually doing various courier jobs for income. While still quite young they become a master flying team and take a job that embroils them in an epic war for dominance of the planet.
—Alan Deikman