Three caveman brothers live a simple life in their cave. The two older brothers enjoy crafting, inventing and building, but the youngest brother just wants to spend his time being kind to others.

One day the cavemen meet a saber-tooth tiger. The older two brothers rush to build a civilization full of inventions to keep themselves safe from the cat. But it is the kindly caveman who proves once and for all that a simple act of kindness is the most powerful thing of all.