In 1870s Missouri, Margaret "Peggy" Thomas and her husband, James, lead a simple and peaceful life, then one day Margaret watches helplessly as James is gunned down on the sidewalk in front of her. Days of mourning turn into weeks and then years. News of the upcoming trial in Arizona of one of the men responsible for James's death rouses the widow from her misery. Neither inexperience nor the prospect of a long and difficult journey will stop Margaret from facing her husband's killer. Along the way, Margaret unexpectedly gains some new companions as she is joined by a free-spirited gypsy woman and a diminutive moonshiner. Together they will face the danger and violence of the Old West, but only Margaret will be able to decide whether she is seeking justice or revenge.