A soccer player, a computer expert, a singer, an artist, and a teacher with a long history of such situations join forces to become Power Rangers and help save the Earth from the scheming of Mesagog, a dinosauric villain who wishes to eradicate all human life and return Earth to the age of dinosaurs. In this season, Tommy Oliver, from Mighty Morphin Power Rangers to Power Rangers Turbo fame, returns as a paleontology professor in Reefside, California. When he is assigned three detention students, Conner, Ethan, and Kira, they end up finding the Dino Gems, paving the way for them to become the Dino Rangers. Conner gains the power of the Tyrannozord (based on the Tyrannosaurus), as well as super-speed; Ethan gains the power of the Tricerazord (based on the Triceratops), as well as the ability to make his skin invulnerable; and Kira gains the power of the Pterazord (based on the Pteranodon), as well as a sonic scream. Tommy (known often as Dr. O) himself once again becomes a Power Ranger by joining the team as the Black Dino Ranger with the power of invisibility, and they are also later joined by Trent Mercer as the White Dino Ranger, with the power of camouflage. Trent must deal with the inner struggle of good and evil, as Tommy himself once had to do as the evil Green Ranger, due to the fact that he gained his powers from a raw Dino Gem in Mesogog's lab, with the powers originally intended to be Mesogog's. Mesogog is in fact, Trent's adopted father Anton Mercer, who, in a faulty lab experiment, began to mutate into Mesogog. Trent later sides with good and saves his father from the mutation. During the course of the series, the team adds the following to its arsenal of Zords: Cephalozord (based on the Pachycephalosaurus), Dimetrozord (based on the Dimetrodon), Stegozord (based on the Stegosaurus), Parasaurzord (based on the Parasaurolophus), and Ankylozord (based on the Ankylosaurus). The Stegozord later combines with Trent's zord, the Dragozord (based on the Tupuxuara), to form the Dino Stegozord. Tommy pilots the Brachiozord (based on the Brachiosaurus), the carrier for all the other Zords. Conner is also given the power to become the Triassic Ranger, and pilots the Mezodon Rover/Megazord (based on the Styracosaurus), which can combine with the Cephalo, Dimetro, Parasaur and Ankylozords to form the Triceramax Megazord. At the end of the series, the Rangers destroy Mesogog with their raw Dino Gem power, but the gems are burned out in the process. Just before this, they are also forced to sacrifice all the Zords in their last battle with Zeltrax, one of Mesogog's strongest minions.Finally they return back to their normal lives.