Dinosaurs did not go extinct. They have been used by aliens as biological terraformers, taming hostile environments and accelerating the evolution of life around the universe. But the dinosaurs have also evolved. And some of them yearn to live free. So a small group escapes their alien slave-masters and seeks sanctuary on a former homeworld: modern-day Earth. Their audacious act causes them to become targets for a never-ending barrage of enemies from all corners of the cosmos.