After witnessing the total destruction of a town called Tonka Flats, agents West and Gordon receive a further threat to destroy the city of Denver. Demanding a ransom, Dr. Horace Humphries, alias "The Falcon", plans to fire a single shell from a falcon-shaped cannon toward this western city. West and Gordon go to an underground hideout in search of the destructive cannon. But once inside, the agents discover syndicate leaders from foreign countries bidding to purchase the massive weapon for their own use.
—Tiff Banks