By seeing Bamm-Bamm having fun with Dino, Barney thinks of buying a pet of his own. At the “Bedrock Pet Shoppe”, Barney and Bamm-Bamm chose an unusual animal: a “Hopparoo”. At home, Fred and Dino are chasing a mouse which frightens Wilma. The mouse goes to Barney’s garage where Hoppy is standing. Both Dino and Fred are scared thinking the mouse has grown big. But Fred sees that it is Barney’s pet. Fred does not like this “hopparoo” at all since it can beat him. But at a family’s picnic, both pets Dino and Hoppy unexpectedly saves them from a close cliff fall…