World War II is raging and the manpower shortage has hit the range since every able-bodied cowboy of military age is off fighting for Uncle Sam. Dad Mathews, a rancher with a huge government contract order for beef, has trouble with the cattle rustlers, led by Henry Judson and Lefty Lewis, who are taking advantage of the situation to steal his herds. John Paul Revere, Special State Investigator, arrives, and upon meeting Mathews' daughter, Betty, gets the idea of recruiting the hard-riding daughters of the district into the WAPS, an organization which will be to the cattle country what the WACS and WAVES are to the Army and Navy. He trains them in military procedure and provides them with radio sending-and-receiving sets. Johnny's sidekick, Frog Millhouse, finds himself the possessor of a "walkie-talkie" which he considers just a "doo-dad" at first, but which is instrumental in the end, in helping Johnny and the WAPS trap the gang of rustlers in their hideout.