A kid raised in the forest swinging a sword suddenly dropped into the real world has to figure out if strength means anything when you don't know the rules. Yaiba's not trying to be cool, he's trying to understand what a samurai actually is while everyone around him is trying to kill him or teach him or both. The show never gets tired of letting him fail in stupid ways first, then come back meaner.

Yaiba grows up in the forest under his father's hard training, determined to become a samurai rather than an ordinary kid. One day he is sent to Japan and collides headfirst with civilized society, a world completely foreign to his isolated upbringing. There he meets the Mine family, the villainous Onimaru and even the legendary Musashi, and he is pulled into a string of dangerous adventures that make him stronger every day. The result is a fantasy adventure that mixes sword-swinging action with plenty of comedy, following a wilderness boy's fish-out-of-water journey.