Three escaped convicts led by Lednov kill three cowboys in Nevada and steal their clothes. They ride on looking for revenge against a rancher, Clay Phillips, who is warned by friend Jed Graham to get out of town.
Clay and younger brother Steve head toward Sonora, California with a herd of horses. They come across four stranded saloon girls, Mary, Marcia, Elaine and Helen, with a broken wagon wheel.
Helen's fiance turns up to take her home. Elaine, who is depressed and ill, flees. Steve saves her and they end up at the Wyatt ranch, where it turns out Elaine is a long-missing daughter. Back on the trail, Helen decides to stay with an Irishman named Fowler who has struck gold.
An argument later leads Mary to steal Clay's wagon, which act is quickly discovered by Clay and Steve. During the short chase, the wagon becomes detached from the horses and plummets into the adjacent creek. Clay dashes into the water and retrieves a semi-conscious and soaking wet Mary, who quickly comes to. Clay's concern for her well-being suddenly returns to anger as Mary, seeing the rest of her clothing floating away downstream, is concerned about that instead of Clay's wagon that she just destroyed. This only solidifies Clay's resolve that she not continue with him and Steve onto Sonora and so puts her on a passing stagecoach to the next town.
In the meanwhile, Lednov, in pursuit, comes upon the camp of Helen and Fowler and so roughs up Helen and kills Fowler to make her reveal where the Phillips brothers have gone. Upon finding them, a gunfight ensues, in which Clay and Steve are victorious, though Steve is wounded. Needing medical attention, Clay takes him to the town doctor where Mary appears and returns to Clay's arms.

Question: What are Clay and his brother Steve bringing to Sonora, California?
Answer: They are bringing a herd of horses. 
Alternative answer: A herd of horses