The plot centered on Calhoun's poker game-win of the incomplete Buffalo Pass, Scalplock, & Defiance Railroad and his attempts to finish the line despite ever-present obstacles.
A running subplot was Calhoun's frequent and (for TV at that time) flagrant sexual dalliances with his many attractive female guest stars, as well as his steadier on and off arrangement with Julie Parsons, played by Ellen Burstyn. Though he was never shown in bed with any of them, there was little doubt about what was happening between scenes; and marriage was never proposed as a possibility. The second season minimized Calhoun's sexual exploits somewhat, perhaps in response to viewer complaints.
Arthur Space as Andy in "Gallows for Bill Pardew" (1967)
Lurene Tuttle as Mrs. Emerson in "Sister Death" (1967)
Michael Witney as Jared Hobson in "The Execution" (1967)
Tony Young appeared three times, as Shad in "No Wedding Bells for Tony" (1966), Red Shirt (uncredited) in "Hellcat" (also 1966), and as Tower in "Banner with a Strange Device (1967).