Bret and his buddy Waco Williams (Wayde Preston) ride straight into trouble in Bent City, where they are suspected of being cattle rustlers.

Hired to protect a cattle drive, Bart dutifully chases Indians — while a masterful swindle takes place right under his nose.

On their way to Denver, Beau and Bart Maverick pick up $6,500 in a poker game at Stop Gap. They decide to wire the money to Denver through the Hulett Telegraph Company. They discover the company is a fake and that the telegraph line leads to a cave two miles away where the crooks stash the customers' money and send phony messages in return. The cousins devise a scheme to recover the money and put the company out of business.

The Fenians, an Irish Revolutionary Brotherhood, are trained soldiers sworn to free Ireland from British rule. The Fenians have gathered in Dakota City to plan a march into Canada where they want to take hold of a small part of British property hostage in exchange for Ireland's freedom. After England pressures the United States to intervene, Beau Maverick is blackmailed into infiltrating the Fenians ranks by a shrewd Army colonel.