A man buys a dull sword and realizes he's supposed to be a samurai. That's the whole premise, and it's enough. This is silent-film comedy from when anime was still learning to walk, and the character designs carry all the weight a voice ever could, they're strange and specific in ways modern shows don't dare try. The animation techniques make every frame feel like someone was inventing the language as they went. You won't understand every beat because the story moves fast and there's no dialogue to catch you. It doesn't matter. Watch it for what it is: proof that anime's earliest creators were weird enough to matter.
A man comes to believe that he was destined to become a samurai. The trouble is that the only weapon he has is a blade he has just acquired, and it is blunt. The question is whether someone so poorly equipped can make his way in the world. The film is a comedy built around that premise.