"I need a man," croons a sultry saloon gal. And she's got one - Chip Coburn, head of the notorious Blue Chip gang of horse rustlers. But somebody else wants her man: U.S. Marshal John Brazos, Chip's brother. A leather-tough tale of frontier justice, Gunsmoke at Tucson belongs to the adult era of Westerns influenced by Shane and High Noon. It's brother against brother theme plays out against a plot that mixes fistfights and shootouts with questions of guilt and redemption. As boys, Chip and john watched as vigilantes lynched their father for horse theft, an event that drove john to the law and Chip away from it. Now Chip wants to go straight, but is framed for murder by a corrupt land baron - and john, on his trail, won't believe his brother has reformed. Mark Stevens (The Street with No Name) stars as Chip. Forrest Tucker, who plays john, would go on to Western renown of a different nature in the TV comedy classic F Troop.