Power Rangers Dino Thunder follows three high school students—Conner McKnight, Ethan James, and Kira Ford—who are assigned to detention with their former science teacher, Dr. Tommy Oliver. During a field trip, they discover mysterious Dino Gems that grant them prehistoric-themed superpowers. They soon learn that Dr. Oliver was the legendary White Ranger and that they must harness these powers to stop the evil Mesogog, a half-human, half-dinosaur mutant who seeks to revert the Earth to the age of the dinosaurs. As the series progresses, the team grows to include Trent Fernandez-Mercer, the White Dino Ranger, who initially struggles with the evil influence of his own Dino Gem. Together, the team must balance their daily lives as students with the high-stakes responsibility of protecting the world from Mesogog's army of Tyrannodrones and powerful monsters. The series is highly regarded for the return of Tommy Oliver as a mentor figure and its darker, more character-driven narrative compared to its predecessors.