Yakari learns from the tribe's elder that the Sioux haven't always been the magnificent riders they are now – indeed, that there was a time they didn't even know what a horse was. Shaken, he speaks a little too demandingly to Little Thunder, wounding his four-legged friend who immediately runs away. Devastated, the young boy will have to track down his companion and find a way to earn his forgiveness if he ever wants to share a gallop with him again...