Lucas and Mark decide to enter a local turkey shoot to raise money to buy a ranch. The competition pits Lucas against the young sharpshooter, Vernon Tippert, who is sponsored by his bullying uncle, Wes Tippert. Although Vernon is a crack shot, he is no match against Lucas's superior skills as a marksman. The dramatic tension in "The Sharpshooter" turns on McCain throwing the match after the competition's promoter threatens to harm Lucas' young son should Tippert lose the competition. The unfolding story shows Lucas McCain reconciling the moral dilemma of protecting his young son and participating in a rigged competition.

"The Sharpshooter" introduced not only the main characters, setting and back story for THE RIFLEMAN series, but also established its thematic distinctions from other popular western adventure programs produced during the Golden Age of television. To be sure, the staples of the genre inform THE RIFLEMAN's storylines—law and order, right and wrong, pioneer spirit and rugged individualism—but the central themes revolve around the father and son relationship—the first primetime television series to portray a single parent raising a child alone—and nuanced morality plays that explored human nobility and very human frailties, foibles and failings, as well as the archetypal white-hatted good guys and black hatted bad guys and outlaws.

Lucas is forced to give refuge to a young bank robber who has been injured while saving the life of Lucas' young son Mark. Trouble ensues when the rest of the outlaw gang appear. The young robber has had a change of heart and wants to go straight, but the gang insists that he will rejoin them. Wanting to help the young man, Lucas is caught in the fight.