In this funny follow-up to Dave's Cave, two lovable cavemen endeavor to make their rocks the very best they can — inventing, in the process, something rather remarkable.Dave loves his rock. Jon loves his rock, too. The two buddies compete over whose rock is biggest, fastest, prettiest, and tallest. When they discover that granite has so much more potential than its natural state, the two friends begin to chisel new shapes, tossing and playing games with their now-rounded rocks. But their woodland friends have other (genius) ideas for how to use these new shapes — as circles with holes in the middle. Anyone up for a ride?