In this story, the villain, Nasty Canasta, steals a large slab of gold from Bugs Bunny, who retaliates by later bankrupting the villain's new casino in San Francisco.
The film opens with Bugs tunneling cross country to meet his cousin, only to run head first into a boulder that turns out to be made of pure gold. While Bugs celebrates this stroke of luck, Nasty Canasta sees this and prepares to steal it while Bugs realizes that he will have trouble safeguarding the gold.
Canasta sets up a simple stand to claim to be a banker who can safely store Bugs' boulder. The rabbit falls for the ruse. However, when Bugs decides to ask for his gold back, Canasta claims the bank is closing and traps the rabbit in the folded up stand while he rides away with the gold. Furious, Bugs vows revenge claiming "You realize that this is not going to be unchallenged."
Six months later, Canasta has used his ill-gotten gains to start a casino in San Francisco ["Nasty Canasta's Gambling H--l"] which is shamelessly rigged in the house's favor. As Canasta prepares for his crooked business, Bugs enters the casino in the role, playing a hopelessly naïve country boy who confuses a slot machine for "one of them new-fangled tele-o-phones". When Bugs uses it to phone his mother for some money, unaware that it's not a telephone, he hits the jackpot and is buried in coins to Canasta's shock. Hoping to recoup this loss, Canasta convinces Bugs to stay for a game and thinks he is maneuvering the apparently easy mark into playing a game of roulette on the pretense of it being a game of marbles. To build his would-be victim's confidence, Canasta arranges for Bugs to win on his first spin, but Bugs develops a winning streak on the same number (#23). Having nearly lost everything, Canasta covers #23 with a block of wood and sets the wheel up for the marble to stop on #00, but when it does his subsequent striking the table in triumph causes the ball to bounce and hammer into the knot of the block of wood, thus landing on #23 yet again for Bugs to win.
Now desperate to win back Bugs' now massive winnings, Canasta convinces Bugs to try playing draw poker and Bugs secretly builds the villains' confidence when he pretends to think the contest involves literally drawing a picture of a fireplace poker. Bugs then follows up on the pretense by pretending to misinterpret Canasta's description of the importance of having the biggest hand to win means blowing up his glove into a giant balloon, causing Canasta to lose his temper at his would-be victim's obtuseness ("CUT IT OUT, CAN'T YA'??!!!"). Bugs uses this as a pretext to walk out, forcing Canasta to grovel in order to coax Bugs to return to the game. Canasta soon regrets doing that when Bugs, after staking all his money, promptly wins with a Four of a Kind consisting of Aces ("A pair of ones, and another pair of ones"), trumping Canasta's Full House.
Now with his casino's bank irreparably broken at the hands of this simpleton who seems physically incapable of losing, Canasta decides to rob Bugs at gunpoint on the pretense of it being another game of chance. Bugs, still keeping in character, naïvely spins the revolver bullet cylinder like a slot machine and a mass of coins inexplicably pours out the gun's barrel.
As Bugs' departs with seemingly all the casino's funds and more, Canasta greedily tries to win money from his gun, only to shoot himself in the attempt, and collapses. Bugs pops in and says to the audience (in his normal voice): "The moral of this story is, 'Don't try to steal no 18 karats [carrots] from no rabbit.'"
When Bugs turns his head at one point, the right whiskers disappear. In the next scenes, the whiskers are restored.
The ending of this cartoon where Bugs (dressed as a naïve country boy) thinks a gun is a slot machine and wins the rest of the gold (in the form of coins) and Nasty Canasta ends up getting shot after doing the same thing was edited on three channels in three different ways :
On CBS, the cartoon keeps in Bugs winning the gold from Canasta's gun, cuts out Canasta doing the same and getting shot, and resumes at the part with Bugs' "18 karats" line.
On "The Merrie Melodies Show," the part where Nasty Canasta spins the gun chamber and aims the gun at his face is shown, but the gun blast is replaced with a frozen shot of Bugs's face (from the last part of the cartoon).
On Cartoon Network, the entire ending was replaced with a repeat shot of Nasty Canasta's face after Bugs beats him at poker intercut with Bugs carrying his winnings in a wheelbarrow.
Barbary Coast Bunny is one of few cartoons where Bugs doesn't munch a carrot.