Bart Maverick is running for office, he is a sure candidate for U.S. Senate. Bart's political ambition has some town's people out for his blood. His opponents will go to any length to stifle his political aspirations; they threathen his life. Fearful of his opponents, Bart finds a way out of the election, without letting the voters down.
Bret is one of the seven owners of a Riverboat who start down the Mississippi for Memphis to sell the broken-down craft, but soon in a deadly game of 10 Little Indians one owner after another is found mysteriously dead. It becomes apparent that if the boat does reach Memphis, it's almost certain it will have but one owner.
Bart Maverick wins big, when he wins the ""Lucky Lady"" saloon in a card game. When Bart goes to Santa Leora to stake his claim, a beautiful Marquesa refuses to relinquish the property to him. Maverick encounters hurling knives, flurry of bullets and pounding fists when he tries to hold onto his newly acquired saloon.
After saving Bret's life, Johnny Rain (William Reynolds) is arrested for robbing a stage coach. While Bret goes to his rescue he becomes ensnarled in a plot that involves a case of split personality. a dance hall wench and a mild-mannered Tinhorn gambler who likes to leave 'em laughing--with hysteria.
Bret is gired by a weathly texan to save her brother Mark from a conniving woman named Melanie. Posing as a Texas Colonel, Bret realizes that he's up against a master crook. With Mark's help and brother Bart's arrival as a weathly Easterner, they set up a scheme to catch the girl and almost outsmart themselves with their own cleverness.
When George Henry Arnett hears that Bret Maverick is in town to collect his money, Arnett (Adam West) starts a ""top gun"" rumor about Bret. After he creates a smoke screen, Arnett creeps out of town. Maverick is idolized by the town youngsters, sought after available women and hunted by the town bounty hunter. Bret Maverick is the talk of the town.
Bret Maverick runs into a notorious bunch of bank robbers; Cole Younger, Billy The Kid, Sam Bass, Jesse James, Frank James, Jim Dalton, Black Bart, Ben Thompson and Belle Starr. The outlaws believe that Bret is the infamous Foxy Smith, a well known bad guy. When the outlaws discover Bret's true identity, they force him to do the robbery in Denver. Bret ends up in a mint of trouble.
Bret Maverick falls for a soft-spoken girl, Modesty Blaine (Mona Freeman). They enter into a partnership — to sell cats to a mining camp overrun by rats. But rumor has it that most men lose either their lives or their money when dealing with this young beauty. However, Bret stands to lose both his life and his money, so he plots to save both.
Beau Maverick (played by James Garner), father of Bret and Bart announces that he is getting married. The Maverick boys discover that the marriage is a business arrangement, not a love commitment. The young girl, Josephine St. Cloud is being forced by her father to marry the older Beau Maverick. The brothers set out to sabotage the wedding plans, not knowing that Beau Maverick already had a plan.