So-So spins the time-space machine and sends the balloon to prehistoric times. Peter removes a thorn from a dinosaur's foot. Now they can't rid themselves of the grateful dinosaur but are elated when the dinosaur saves Peter from an attacking caveman. The dinosaur, imitating Peter's hippo hurricane holler, accidentally sucks the balloon inside his belly. Peter and So-So, on the balloon still inside the dinosaur, float off.
