When intergalactic herders Carl and Ruby Cadet find a Raider baby in a wrecked spaceship they decide to keep her as their own daughter. Raiders are considered the scourge of the galaxy and the Federation, never having captured a Raider alive, demands they give her up. When Carl and Ruby refuse, the Federation declares Carl and Ruby outlaws and sends Raider hunters after them. The hunters have been given an order: capture the baby alive but eliminate Carl and Ruby if they have to. Despite the danger, Carl and Ruby decide to go rogue and flee. Their only hope of saving themselves and the baby Raider lies with their space-travelling horses, and the mysterious Horse Passages.