Season 4, Episode 12 - LI: Young Jack in Africa
This episode takes place during Jack's childhood. After Aku's first attack, Jack is brought to a tribe in Africa where he is admitted into the adult community after a small ritual and the chief of the village teaches him the art of fighting with a stick.
But an enemy tribe attacks the village in order to get a reward promised by Aku for Jack's capture and everyone is captured except for Jack. So he follows them, mastering the captors' weapon, using qualities of the animals he has observed to do so. After a difficult series of fights, Jack releases all the prisoners and with their help, the enemy tribe is defeated. At the end, Jack leaves the tribe because he is now considered to have learned all he can from them.