When Casey Sue Thornton's reverie is disturbed by a group of riders led by a mean-spirited cowman intent on hanging a young handsome cowboy, she does not hesitate to intervene and uses her Winchester to wound one of the riders and sends the rest fleeing for their lives. The cowboy, Brazos Kincaid, immensely grateful to this young boy who has saved him from a certain lynching, boldly claims they are now partners. Casey Sue, who introduces herself as Case, has had to resort to disguising herself as a boy for her own safety and has become rather proficient after years of pretense in order to survive in a man's world. Casey Sue is not in the market for a partner, for she is on her own furtive mission to fulfill the promise made to her dying uncle. Disguised as a boy she is wary that Brazos should discover her true identity. Even though she has saved the man's life she is not certain she can trust him and so meticulously keeps to her boy's disguise. But to her disgust he seems to enjoy entertaining her with boorish stories of his love life. But his easy-going manner and handsome good looks make it hard to rebuff and she reluctantly agrees to ride with him to the next town. When Casey Sue attempts to slip away from Brazos and continue on her own, it nearly results in Brazos' life. And after Casey Sue is attacked and beaten it becomes clear to Brazos Kincaid that there is no possibility of letting Casey Sue face alone those who will stop at nothing to pursue their fever lust for gold.