The setting is in old California when it was under the rule of Mexico. Don Hernando is a powerful feudal lord who is arrogant and cruel. Padre Ernesto is a noble priest, greatly beloved by his congregation. In trying to save Pepe, an Indian slave of Don Hernando's, from being punished by the latter, the Padre is struck and mistreated by the Don. He bears no resentment, however, and later, when the Don is stricken with the dread disease, smallpox, it is none other than the Padre himself and Pepe who risk their lives to nurse him back to health. But just as Don recovers, the Padre is himself stricken with the disease, to which he succumbs. Pepe is heartbroken, and from that moment swears to avenge himself for the Padre's death by taking the life of the Don. Pepe brings up the rear of the funeral procession, but instead of entering the Mission, lays in wait for the Don. Don Hernando comes and pauses. Pepe sneaks up behind him and raises high in the air the knife that is to strike the blow. With full force he brings it down, but at that very moment the Don falls upon his knees in prayer, truly repentant of his crimes, and an almost supernatural power stays Pepe's arm. Master and slave are reconciled and lead different lives under "the new light."