The Mission Santa Maria catered to Sundown's needs until bandits murdered their nuns. The young Maria is the only survivor, yet the massacre she witnessed sends her into an endless sleep. For two years she lies unconscious in the mission, gradually becoming weaker, before Bishop Finnegan notices. Unsympathetically, he decides to close the mission, which is sure to speed her demise.
With her outlook quickly becoming bleak, the devious snake-oil seller Fergal O'Brien rides into town. Although Fergal is typically interested in making a quick dollar, Maria's plight touches him. He attempts to wake her with what he claims is his universal remedy. Not surprisingly, though, his tonic fails.
An undaunted Fergal vows to help her by persuading Finnegan to keep the mission open. The bishop, however, decides that the lawless Sundown is too dangerous for a mission. The only options are to hope for a miracle or clean up Sundown with fearless gun-toting skills. Unfortunately for Fergal, though, he has never used a gun in his life.