Bad guy, Hammond, (Francis McDonald) doesn't want Idaho to join the Union - there's a public vote coming up - because that might mean more law and order, perish the thought.
Standing in the way of the boss crook (and his familiar crew of B western heavies) are brave young government agent Vic Gordon (George J. Lewis) and a mysterious masked avenger, the Black Whip, in reality newspaper owner Barbara Meredith (Linda Sterling).
That's about the entire plot actually. Hammond spends much of his time on screen issuing generalised instructions to his snarling henchmen.
"So, there's a wagon train of settlers coming in, eh? Take some of the boys and make sure it never gets here!" "So, the newspaper office is expecting a new printing press to replace the one we smashed, eh? Take some of the boys and make sure it never gets here!" Etc. Etc.
These are not actual quotes but you get the picture, I'm sure.
So, no prizes for script, plot or acting but a big star rating nevertheless because Zorro's Black Whip is so brilliant in every other way. As soon as you see Yakima Canutt's name in the opening credits, you know you're in for a treat.
Tremendous, brilliantly choreographed fights in every episode with whole rooms full of furniture reduced to rubble and dust; chases on horseback with the horses galloping at around 200 miles per hour - the film may have been speeded up a little at times - shoot outs by the dozen with no time wasted in bothering to re-load and all the usual "impossible" episode endings. Our heroes are blown up, tipped over cliffs, set on fire and subjected to various other indignities, often escaping death only by the insertion of an added sequence in the next chapter. Republic were just so good at this kind of thing! Another reviewer suggested that this was aimed at an audience of 10 year olds. I agree, but that doesn't mean that it can't be hugely enjoyed by those of us who are just big kids at heart.
Two final thoughts: I love that recurring shot of the waterfall hiding the Black Whip's secret cave and, er, where did Zorro get to?