At the Red Ox, Bret Maverick is organizing the construction of wine racks for the upstairs room. Mary Lou wants him to check the copy for his new advertisement for thirty cases of rare wine and he orders 3,000 handbills from her. Tom has rigged a special suspension on the wagon and reluctantly turns over the money they're going to use to buy the wine at auction from Amos Ingersoll in Tucson. As they take the road to Tucson, they pass two brothers, Barney and Kenneth Broomick. Barney tells his younger brother not to shoot anyone if he can avoid it. They both recognize Bret and figure that he'll lead them to the woman that they're after. Barney says that they're doing the Lord's work and insists that he only kills when he has to.
In Tucson, Bret and Tom check into the hotel. Tom suggests they put their money in the hotel safe, but Bret hides it in a secret compartment in his bag. They go to lunch, unaware that a woman, Hallie McCulloch, is in the lobby. She tells the desk clerk that she's Mrs. Bret Maverick and asks for the key to Bret's room. Once inside, Hallie searches the room and knows just where to look to find the money.
Kenneth and Barney ride into Tucson and wait outside the hotel. Barney complains that Kenneth gave them away in Phoenix by sneezing, and complains that it's his brother's fault that he's not a minister. They know that Hallie sent a letter to Bret and figure that Bret is her last friend. When Kenneth points out that Dixie might not have their money, Barney says that they'll rob another bank if they have to and take it to Fort Smith, Arkansas.
Tom and Bret return to the hotel and are informed that "Mrs. Maverick" checked in. They go to Bret's room and confirm that she took the money. Bret points out that only Amos knew they were coming and he wouldn't have stolen the money. He asks the desk clerk for a description of "Mrs. Maverick" and recognizes the woman as Hallie. He tells Tom that they'll get their money back with interest, and Tom has already checked and confirmed she told the hack driver she was going to El Paso. Bret doesn't believe it and figures that she has gone to ground in Tucson to con someone else for money.
Dixie goes to a tea room and poses as a widow to convince Captain Rufus Pinkerton, an investor, to help her sell off her late husband's estate for $4,000. Bret and Tom come in, spot her, and Bret breaks up the deal by claiming that Hallie is the deluded wife of a Texas Senator. Pinkerton lets them take Hallie away rather than offend the senator, and the two men take Hallie up to her room. As Bret goes through Hallie's bags, he informs her that Pinkerton is with the Pinkerton Detective Agency and would have arrested her if they hadn't gotten her away.
Bret finally finds the money hidden in a hand mirror that he gave her years before. Tom grabs the money and leaves them to argue. As soon as he's gone, Hallie appeals to Bret for enough money for a meal and he agrees. At dinner, Bret orders a bottle of the rare wine and tells Hallie about how he's settled down and spends a lot of time taking it easy on his own ranch. Tom tracks down Bret and tells him that he's checked and that Amos Ingersall died of the gout a year ago and there's no wine auction. Bret realizes that Hallie wrote him a fake letter from Ingersall to lure him there. When the waiter comes back with the wine, Bret tells him to pour it in Hallie's lap and leaves with Tom.
Hallie returns to her hotel room and discovers that someone has torn the place up. Barney is hiding in the wardrobe and tries to get out to attack her. Hallie slams the door, trapping him, and gets out the door as Kenneth comes in through the window.
Bret and Tom go back to Sweetwater and break the news to Jack and Mary Lou that there's no wine. As the workers start bringing in the wine racks, Mary Lou wants payment for her handbills and Bret makes a hasty exit. Tom invites Mary Lou into his office and gives her a present that he bought for her in Tucson, a rare German camera lens. They start to kiss but Jack calls Tom away to handle a fight.
Hallie arrives in Sweetwater and asks Rodney where she can find Bret. He's surprised when she introduces herself as Mrs. Maverick. Meanwhile, Barney and Kenneth have tracked Hallie to Sweetwater and are riding toward the town.
Bret hears that Hallie is in town and claiming to be his wife. He goes to the hotel and asks why she followed him to Sweetwater. Hallie claims that she came to return a pair of cufflinks that she stole from him two years ago. When Bret doesn't buy that, Dixie says that she wants to settle down and breaks into tears, but he doesn't believe that either. He tells her to hit the trail but Dixie says that she plans to stay in Sweetwater.
Bret goes to the Red Ox to work out what to do with the wine racks. Mary Lou and Rodney are there and try to ask Bret about his "wife." He insists that he isn't married but they don't believe him. Tom can't resist embarrassing Bret by supporting Hallie's claim. When she comes in, Bret hastily escorts her out and takes her to the Lazy Ace, confident that Cy will scare her off.
Later, Kenneth and Barney arrive in town and go to the Red Ox to find Bret. They tell Jack that they're fans and want to pay their respects, but the bartender refuses to give them directions to the ranch.
When Cy learns about Hallie, he refuses to cook or clean for her. Hallie comes in and quickly charms the foreman. However, when she threatens to redecorate the house, Bret quickly leaves to go fishing and let them settle things out. Cy warns Hallie to either stay out of the kitchen or work there full-time and Hallie offers to redecorate and compliments Cy on his carvings. He quickly agrees to let Hallie have her way and she moves Bret's portrait of Pappy to give Cy's carving a place of honor on the mantelpiece.
Bret comes back later and finds Cy and Hallie cheerfully cooking together. The gambler tries to warn Cy without success and figures Hallie is up to something. She insists that she's just there to get married and has already unpacked things in her room. Bret sleeps on the couch that night but wakes up just as the Broomick brothers break in. A fight breaks out until Cy interrupts them with a warning shot from his shotgun. Barney explains that he's been robbing banks and wagons for years, but decided to start preaching the Gospel. A minister in Fort Smith, Arkansas, has offered to teach Barney the trade in return for $2,400. Barney robbed a bank and got exactly $2,400, but Kenneth lost the money to Hallie in one of her cons. They want to get the money from Hallie, but Bret points out that if they kill her then they won't get the money.
Barney agrees to leave for the moment, and Cy complains that Bret is abandoning Hallie. Bret refuses to help her. Hallie, who has overheard the entire thing, asks Bret for a hug. He takes her back into his room and she admits that she's tired and scared. Hallie had hoped the Broomicks would give up but they just keep going. Bret tells her that he's bought her some time and they kiss.
The next morning over breakfast, Hallie tells Bret that she conned him to come to Tucson and stole his money to pay off the Broomicks. Bret tells her that she'll have to pay Barney off and she asks for a loan of the money until the heat is off. Bret refuses and leaves. Cy catches up to him and complains but Bret warns that he can't pay off everyone that Hallie has swindled.
Hallie sneaks into Bret's room and finds his stash of $3,000 sewn into the cover of a Bible. After pausing briefly to contemplate the bed she shared with Bret the previous night, Hallie leaves.
Back at the Red Ox, Tom is busy complaining to Bret about his schemes. Jack informs them that the Broomicks have left town. Cy tells Bret that he gave Hallie a horse so she could get to Phoenix to tend to her dying mother. The foreman figures that Bret gave her the money, but Bret says he isn't that dumb and she must have got the money to pay off the Broomicks on her own. A chicken farmer, Sloatman, comes over and offers to buy the wine racks from Bret.