Synopsis: Rip Hunter invents a pair of Time Spheres which allow him to travel backwards in time. On the initial voyage, he travels to the Mesozoic Age with his assistant Jeff.
While Rip is gone, criminals break into his lab and force Rip?s friend Bonnie and her younger brother Corky to take the other Time Sphere into the past as well. The Time Sphere is damaged upon arrival stranding Bonnie, Corky, and the criminals. To escape they search for Rip and Jeff. The crooks locate Rip?s time sphere and hide it, then they fall into a river and are swept away.
Rip and his companions begin looking for the hidden time sphere, braving the dangers of dinosaurs and an erupting volcano to find it. When they do find it, the crooks return, so Rip takes replacement parts from the Sphere, then sends Bonnie and Corky back to the present. Rip, Jeff, and the crooks find and repair the other Time Sphere and escape a dinosaur stampede before returing to their own time period.Synopsis uses material derived from dcindexes.com
Notes: Story has three chapters. Chapter two: "The Modern-Day Cavemen". Chapter three: "The Great Beast Stampede".