Buffalo-Seed complains to Yakari that he is having trouble sleeping. He’s been having a recurring dream in which his ancestor appears to him, telling him about a hidden object that will make Buffalo-Seed a proud and strong Sioux. The only clues to help solve the mystery are “the buffalo’s horn” and “the stones that speak”. Yakari leads Buffalo-Seed to “the buffalo’s horn”, a plain where all the horned creatures gather. Thanks to his ability to talk to animals, Yakari finds a little bag on the plain, containing stones with strange drawings on them. It’s a puzzle, and Restful-Rock helps to decipher it: it’s a message from Buffalo-Seed’s ancestor, which makes reference to the precious object. But they’re missing a piece of the puzzle, the very piece that reveals where the object is hidden. Unbelievably, the stone that Buffalo-Seed has always worn around his neck is the missing piece. A faded drawing on it describes “the tree of the ancients”, located in a hard-to-reach valley. This time, demonstrating more wisdom than he is known for, Buffalo-Seed advises them to proceed with caution. They arrive safe and sound at their destination, and find a magnificent arrow and quiver buried at the foot of the tree. Buffalo-Seed is overcome with emotion.