A crooked real estate manipulator sells worthless land on mortgage to flood refugees, then tries to profit by reselling the land to the state, committing murder in the process, as the Three Mesquiteers work to bring him and his gang to justice.

Four flying G-Men protect America against enemy spies; one of the four assumes the identity of The Black Falcon, to befuddle the saboteurs even further.

In 1924, stage-struck Boston blueblood Hannah Adams picks up musical star Tim O'Connor and takes him home for dinner. One thing leads to another, and when Tim's show rolls on to Chicago a new Mrs. O'Connor comes along as incompetent chorus girl. Hollywood beckons, and we follow the star careers of the O'Connor family in silents and talkies.

Suburban Paradise Park becomes a heaven for social-minded Mrs. Alice Summers (Mary Boland), when she accidentally causes the apprehension of two bank robbers after walking into the bank during the robbery and one of the robbers, in taking money from her purse, left his fingerprints on the purse. She is made an honorary police captain and, with her society sisters sets about "keeping lawlessness" out of the town. From that point on, life becomes miserable for her hen-pecked husband Calvin (Ernest Truex).

The Three Mesquiteers are forced to track down a train robbery ring after some of the gang hijack their truck for a getaway and the police conclude they are part of the gang, an identification which is just fine with the gang's nameless chief.

Young Brad Craig enters the military school with a chip on his shoulder which upperclassmen quickly knock off. Once adjusted, Craig falls in love with a professor's beautiful daughter, only to find she is in love with his roommate.

Unable to legally capture and sell a herd of protected wild horses, corrupt rancher Rance Macgowan uses his trained killer horse, Volcano, to substitute for the real leader of the herd and cause havoc and death among the ranches. With the government about to drop the restrictions on rounding up the herd, the Three Mesquiteers find themselves in the middle of the controversy after their friend, Sheriff Miller is killed by Volcano.

Autry and his buddies have a horse selling business which is threatened by a tractor company which claims horses are out of date.

The Cattlemen's Association has called in the Mesquiteers to find cattle rustlers. They get Tex Riley to pose as Stony so Stony can arrive posing as a wanted outlaw. This gets Stony into the gang of rustlers and he alerts Tucson and Lullaby as to the next raid. But Hartley is on hand and unknown to anyone is the rustler's boss and he joins the posse with a plan that will do away with the Mesquiteers.

Two con artists join forces and pose as brother and sister. He then meets rich widows through the "personals" sections of newspapers, marries them, and both kill the widows for their money.