Walker's Rules by Joannie Kay

Jessie is determined to find her little brother, but fate has other plans when she's caught in a stagecoach robbery. Forced to disguise herself as a boy to avoid detection, Jessie's troubles only deepen when she's sent to Walker's ranch—a place meant for wayward boys. But Walker's life takes a drastic turn when he discovers that Jessie isn't a boy at all, but a spirited young woman. To protect her honor, the judge decrees a new sentence: marriage. Now, Jessie is bound to a man she'd rather ...