In the Old West, bravery often comes in the form of a squared-jaw gunman with a tin star pinned to his chest. But in 1875, in the dusty town of Trinidad, Colorado, bravery wears a cross. When Sister Blandina, a 22-year-old missionary from the Sisters of Charity, arrives in Trinidad to open a school, the father of one her students is arrested for attempted murder. The Sister visits the man in jail to see if she can help, and she suddenly finds herself facing down a bloodthirsty mob of vigilantes, intent on taking the law into their own hands. With the help of the lone sheriff, Casimiro Barela, she bravely escorts the condemned man through the crowd of angry citizens to seek forgiveness from his dying victim. Years later, gunfighter-turned-newspaperman Bat Masterson visits Barela, now a senator, to hear the incredible tale of Sister Blandina and the killer.