 This is the first of the 51 films (1936-1943) Republic made as "The Three Mesquiteers" series and, as such, it did not, as shown im Movie Connections, "follow Powdersmoke Range or Law of the  45s",since the characters were never identified as "The Three Mesquiteers" in either of those films, and only two of the characters appeared in "Law of the 45 s" and one of the character names was 50% changed in that one.Well,to be precise, it did follow those two films in terms of release dates but those two films have no connection (other than William Colt MacDonald) to the "Three Mesquiteers" series of film from Republic. This 1st "Three Mesquiteers" film opens with hundreds of World War I veterans and families, led by Lullaby Joslin (Syd Saylor), rushing into the rich grazing lands of San Juan Basin, New Mexico,to file on homesteads just opened by the government.The straggling army vets meet much opposition from the cattle owners, especially the Canfield brothers (J.P. McGowan and Alan Bridge),who want to keep their government leases for grazing purposes.Coming to the aid of Lullaby and the homesteaders are Stony Brooke (Bob Livingston) and Tucson Smith (Ray Corrigan), a couple of happy-go-lucky trouble shooters. When Bob Bryant (Gene Marvey), one of the homesteaders is killed, leaving alone his beautiful sister, Marian Bryant (Kay Hughes), who is getting courting attention from both Stony and Tucson, they organize the veterans as a fighting unit and go into action against the Canfields and win. At the end, Lullaby joins Stony and Tucson as they ride away into the mesquite brush as "The Three Mesquiteers" in the first film of the series.Syd Saylor was cast as "Lullaby" on a one-picture deal only, and was replaced by Republic term-contract player Max Terhune playing the role. Saylor was not replaced because, as some film historians have written, "the exhibitors and audience didn t like him." (Although there was always a lot about Syd Saylor performances not to like) The second film in the series was already in production before "the exhibitors and audience" saw this one.Republic remade this as another "Three Mesquiteers" film in 1940 as "Oklahoma Renegades."