Dr. Tommy Oliver barely escapes from a mysterious island crawling with dinosaur mutants before it explodes. Some years later, he lives a quiet life as a high school science teacher. But when the evil saurian overlord Mesogog sets his sights on bringing back the age of dinosaurs, Tommy jump-kicks into action by collecting the Dino Gems. These artifacts choose three unlikely teens from very different worlds with a Dino Thunder power-up (ha!) to defend the world. As their battles with Mesogog and his minions rage on, Tommy becomes a Ranger once more and another young man with secret ties to a very divided Mesogog joins the legacy of power.