In the future, Earth is ravaged and devastated by strange plant-life, fungi, plagues, and many more biological weapons, remnants from the last war. Humans on Earth survive in small ground communities, and on mighty airships that never touch the ground.
Those who control the airships call themselves the Sky Lords, they demand tribute from the ground dwellers and live like kings. But the situation of the ground dwellers grows worse, the bio-contamination spreads and is harder to fight with each passing year, and soon there might be no ground communities from whom the Sky Lords could demand tribute, and they need the tribute to survive themselves.
A delightful little trilogy whose strongest point is probably the depiction of a post-apocalyptic world that is devastated not by atomic but by bio-weapon fallout. There were times when the story seemed to treat water without going forward, but often there was enough action to distract from that, still, the plot could have been tighter. Something I thought was impressive was one of the antagonists, who was so ambivalent to the plot that I was never sure whether I should root for him or damn him.
Overall the trilogy was good fun, had some unexpected and cool plot twists, and a very satisfying and thoughtful ending.