Philo gets his first D grade after failing to finish his science project. It's up to him to finish the project with help from the gang so he can get an A. With help from fellow inmates Piggy McGrabit, Trash Man, Teddy Bear Snatchter, and Yuckster, Mr. Bad escapes from prison. He transforms Captain Caveman into a dog with poisoned hot dogs. Cavey Jr. hunts down Mr. Bad for the antidote and to get him back to prison before the poison causes Captain Caveman to permanently remain a dog.