Back in Time is a episode of Dinosaur Train season 3.
Buddy and Tiny start wondering aloud whether the Triassic was the beginning of time, and if there was anything before the Age of Dinosaurs. So, to the Dinosaur Train they go where Mr. Conductor takes them back to the beginning of the Triassic time period to get some answers. In the Triassic, Buddy, Tiny, Mom, and Mr. Conductor meet up with Erma Eoraptor who is happy to explore the “before the Triassic” question with them. Our group walks through a Pedestrian Time Tunnel (that’s beyond the end of the train tracks) to get to the Permian Time Period, the time period immediately before the Triassic. There, they meet Deon Dimetrodon, who has never met a dinosaur or pterosaur before. Buddy and Tiny are amazed to learn that there are neither in the Permian (or earlier)! Deon marvels at our family’s features – especially Tiny and Mrs. Pteranodon’s wings. Deon shows our group around the hot and humid Permian, and he explains how his sail fin keeps him cool. Then Deon is delighted to experience the Mesozioc Era. He walks through the Pedestrian Time Tunnel with our group, and is blown away by the vegetation and the variety and size of dinosaurs. Another lifelong friendship is forged!