 On alien worlds Terrans fight brushfire wars and thereby help Central Control maintain peace within its vast interstellar empire.Archs, who fight with relatively primitive weapons, are organized into Hordes, which fight on underdeveloped barbarian planets, and Mechs, who fight with more modern weapons, are organized into Legions, which fight on advanced, civilized worlds.But then a Horde fighting on the medieval planet Fronn encounters a Legion of Mechs.