Dan Mitchell (Randolph Scott) is the town marshal of Abilene, KS, in the turbulent years after the Civil War and the start of the big cattle drives out of Texas. The town is growing faster than a lot of citizens are prepared to deal with it, especially as homesteaders start moving in, fighting for space with the cattlemen. Dan has kept the peace, such as it is, by keeping the saloons, gambling, and guns on one side of Main Street and the shop-owners, farmers, women, and children on the other. He's also been walking a tightrope in his own life, conducting a sometimes turbulent romance with Rita (Ann Dvorak), a saloon singer and co-owner, while also not discouraging the attentions of Sherry Balder (Rhonda Fleming), the "nice girl" daughter of one of the town's leading businessmen, who would love to marry Dan if only he would settle down. A new wave of homesteaders is arriving, and the cattlemen, cowboys, and saloon owners want them driven out and the town kept wide open, fearing the homesteaders' religious beliefs and the arrival of families, which means schools, building, and encroaching "respectability." Trouble breaks out and people are killed, with Dan caught in the middle. Using his guile and a good deal of bravery, and the unwitting help from the cowardly county sheriff (Edgar Buchanan), Dan manages to get the shop owners onto the side of the homesteaders, and plays a dangerous game of divide-and-conquer with the saloon-keepers and cowboys.