Gilda exits the Hotel Centenario (after her tete-a-tete with another man) and finds Johnny parked outside at the appointed hour (2 AM) to drive her home. Upon their return, she entices him with a sultry reminder that they are alone:

Gilda: Ballin was wrong, wasn't he?
Johnny: About what?
Gilda: He said you can shut out excitement by just closing your door. You can't, can you?
Johnny: I don't know what you're talkin' about.
Gilda: I was just mentioning how quiet it was in the house. There isn't anybody here but us, you know. Everybody's celebrating Carnival.

But Johnny again wants to be loyal to his master and not betray his boss by taking advantage of the situation. Still angered by her, he wants to punish her for not being faithful to Ballin. He is spiteful of Mundson's duplicitous wife, as he explains - in voice-over:

I couldn't get it out of my head, what she said about nobody being in the house but us. I thought of Ballin back in the casino fighting for his life, and this little...I knew that all his plans, all his dreams of greatness would be wrecked because of what she was doing to him. I knew he wasn't strong enough to throw her out. I knew it was up to me. I had to get rid of her for him.

In the upstairs bedroom, as Johnny commands Gilda to get out, their mutual hatred turns to love when he 'drops his mask' and succumbs to her whispered advances - after she equates two opposite emotions: hate and love:

Johnny: Get your clothes on. You're gettin' out of here.
Gilda: Are we, Johnny? Are we?
Johnny: Not we! You!
Gilda: (Her face is darkly shadowed.) You do hate me, don't you, Johnny?
Johnny: I don't think you have any idea how much.
Gilda: (She approaches closer to him and echoes Mundson's words.) Hate is a very exciting emotion. Haven't you noticed? Very exciting. I hate you too, Johnny. I hate you so much, I think I'm gonna die from it. Darling. (She falls into his arms and they kiss passionately.) I think I'm gonna die from it.

A second kiss is interrupted by the loud sound of a closing door from outside the bedroom. Johnny catches a glimpse of Mundson hurriedly leaving. After overhearing their passionate conversation, he mistakenly believes that Johnny and Gilda have consummated their relationship, and decides to leave for multiple reasons.

Johnny (and Obregon's police car following him) race after Ballin to a private airstrip and is presumed dead (they both watch a suicidal airplane crash into the ocean). [Note: Unknown to everyone, the crash is faked since Mundson has parachuted into the water where he is picked up by a boat en route to a seaplane. To an accomplice who picks him up in the water, Mundson explains that he staged the crash in order to elude the police's investigation into the murder of the German, and escape further questions about his corrupt and troublesome Nazi cartel dealings: "An unfortunate murder. The detective Obregon knows that I did it. I'll stay away as long as necessary - and then I'll go back - and attend to something."]

The two reunited lovers guiltily think that they are responsible for Mundson's (faked) 'suicide.'

Ballin's will leaves everything to Gilda (his estate and fortune, with Johnny as "sole executor"), while Johnny takes over as head of the powerful, crooked cartel. Mundson was fronting for an international tungsten cartel controlled by former Nazi officials who had escaped from Europe - their first step in politically and financially regaining power after the ignominious defeat in the war. Johnny describes the organization (in voice-over):

I finally had them in my hands, the little pieces of paper that Ballin said would let a man rule the world. But first, I was puzzled, because it didn't seem like much. A tungsten mine and a few patents. A dozen or so small corporations joined together to form one organization, with Mundson at the head. But then I saw the potential power of such a group, saw how it could grow and spread and gobble up anyone who dared stand alone against it.

Johnny replaces Mundson in two significant, well-matched ways. He assures other board members and stockholders: "It's gonna be business as usual." And he becomes head of the monopolistic, evil cartel. And he also recreates himself as Mundson by taking Gilda as his wife, and he turns their marriage into a punishing trap. He marries her to punish her for constantly betraying Mundson. The camera peers through a rain-swept window to observe their marriage ceremony before a judge. The rain ends as they leave the judge's chambers, and Gilda optimistically interprets the change as a portent of good: "Maybe that means something."

In their new, plush apartment, Gilda is relieved that they are a couple again:

Gilda: You think of everything, don't you, Johnny?
Johnny: Everything.
Gilda: We're right back where we started. Aren't we, darling? (She hugs him) Right back where...

However, she is startled to see that Johnny has chosen to mount an imposing portrait of Mundson in the living room - a memory of her icy ex-husband. She pauses after seeing the portrait for the first time:

Johnny: Right back where we started.
Gilda: Johnny, Johnny, that isn't even decent.
Johnny: What was that word again, Gilda?
Gilda: Decent. I said, 'decent.'
Johnny: That's what I thought ya said. That sounded funny comin' out of you, Gilda.

Johnny hatefully distrusts his new wife and makes her existence an imprisoning trap in Buenos Aires (fulfilling the previous toast: "Disaster to the wench"):

(voice-over) She didn't know then what was happening to her. She didn't know then that what she heard was the door closing on her own cage. She hadn't been faithful to him when he was alive, but she was gonna be faithful to him now that he was dead.

Johnny replaces Mundson as Gilda's emotionally-abusive, misogynistic husband in a continuing love-hate relationship. He is unable to trust her and he punishes her for her 'sins' - believing that she was always cheating on her ex-husband. Johnny orders Casey, the casino's strong-arm employee, to restrict Gilda's movements:

From now on, you're to stick with Mrs. Mundson - Mrs. Farrell. Whatever she does, wherever she goes, you oughta be there. She's not to talk to anyone, and no one's to talk to her. You get that?

The subplot about the Germans controlling the tungsten business with patents emerges again. [In a 'gentleman's agreement' during the war, Ballin purchased and acquired the patents with a unwritten promise to return the patents following the war, and became head of the tungsten cartel.] One of the German representatives questions Johnny's acquisition and retention of the patents, without releasing them back to the Germans as Mundson had promised. Johnny asserts that it was only a "gentleman's agreement" and that he is under no obligation to release them back:

German: You've seen that the patents are German, haven't you?
Johnny: They were. Originally.
German: Exactly. They belong to my principals.
Johnny: Not anymore.
German: Three years ago, when it began to seem that Argentina might find it necessary to declare war against us, we made an arrangement with Mundson. We allowed him to buy our patents.
Johnny: Good idea. The casino here makes a nice front.
German: We even advanced him the money with which to buy them from us....We had an agreement with Mundson that at the end of the war, he'd turn our property back to us....It was a gentleman's agreement.
Johnny: I see. And Mr. Mundson wasn't a gentleman?
German: He was a madman, Mr. Farrell. He thought he could rule the world alone.

As dictatorial leader of the casino, of his wife, and of the German cartel, Johnny systematically ignores and shuns Gilda, and remains full-time at the casino, while she waits "all dressed up" in their apartment for him. Impatient, bewildered and feeling caught in a despised, 'living hell' of a marriage, Gilda finally decides to confront Johnny and question the icy treatment she is receiving: (voice-over) "But a girl like Gilda couldn't stand not knowing the WHY of things, so she decided to swallow her pride and come to see me."

In a revealing strapless dress, she confronts Johnny in the casino office and pleads with him for an explanation:

Gilda: Hello. Remember me? I'm Gilda, your wife. Remember? You haven't been around lately. I thought maybe you were an amnesia victim or something. Got a light? (She must stoop down to light her cigarette.) You don't look so hot, you know that? You're losing weight. This vacuum I'm living in. Mind giving me a reason?
Johnny: Not at all. You had such a full life up 'til now, I thought a little peace and quiet would do ya good. Give ya time to think.
Gilda: Think about what?
Johnny: Would it be too corny to say 'your sins'?
Gilda: Yes, it would.
Johnny: Well, I said it.
Gilda: You're cock-eyed, Johnny, all cock-eyed. I figured that's what the deal was. You're getting even with me for something. Hmm. We're great people for getting even, aren't we, Johnny?
Johnny: Are we?
Gilda: Aren't we? Didn't I get even with you for walking out on me, by marrying Ballin?
Johnny: Great, that's just great. The man's dead and...
Gilda: And I'm glad. What do you think of that? He was insane, Johnny. I was afraid all the time.
Johnny: (sarcastically) You acted like it.
Gilda: Johnny. There's never been anybody but you and me. All those things I did were just to make you jealous, Johnny. There's never been anybody but you and me.
Johnny: Not anybody?
Gilda: Not anybody.
Johnny: (He grabs her violently) What about your husband? If you could forget him so easily, you could forget the others too, couldn't you?
Gilda: But there weren't any others, Johnny!
Johnny: When you admit them, when you admit them and tell me who they were... (He pushes her away)
Gilda: You wouldn't think one woman could marry two insane men in one lifetime, now would you?

In anger and retaliation, Gilda flees from her horrible relationship and arranges more trysts and dinner dates with other men. Johnny narrates (in voice-over) how he continually would break up any of her flirtatious, public encounters:

(voice-over) She wasn't scared yet, because she didn't quite realize, yet. Right now, she was, she was just plain mad and she was hitting back...She just reached out for anyone. They weren't hard to find for a girl like Gilda...but wherever she went, whatever she did, it finally got to her that Buenos Aires was her own private prison. That's when she decided to run away. She went to Montevideo and got a job singing in a nightclub, started divorce proceedings, and met a man.

Realizing that it will do "no good" to run away to a different country where a divorce decree wouldn't be recognized, Gilda returns to Buenos Aires to get a legal annulment from her marriage to Johnny - but she is deceived by her new, persuasive lover named Tom (one of Johnny's hired thugs posing as an affluent lawyer) and brought back to Argentina. As she enters their room at the Hotel Centenario, she realizes that she has been deceived - there sits Johnny calmly smoking in an armchair as Tom backs out of the room behind her. Johnny tells her that her interminable punishment will continue unabated: "There's no such thing as annulment in Argentina." Becoming hysterical, she slaps him repeatedly across the face, beats on his chest, and then slumps to the floor in front of him. She grovels at his feet and begs for freedom from torment - literally feeling 'blamed' and trapped as a wife. [This is similar to the theme song she often sings about men's blame of women, Put the Blame on Mame]:

Oh Johnny, please let me go, please let me go. I can't stand it anymore. I don't want anything from you. But please, just let me go.

Meanwhile, police inspector Obregon (Joseph Calleia), who has been scrutinizing the casino's underlying criminal activities and trailing Mundson/Farrell throughout the entire film, threatens to close down the casino: "Why do you think we've allowed the casino to stay open? Because a smart cop doesn't arrest a purse-snatcher if the thief will lead him to the bigger crime....We know you're the head of a tungsten monopoly, Mr. Farrell. What we want to know is the names of the participants." Johnny is distracted by the casino's floor show, the stage upon which Gilda makes her grand entrance.

The film's most memorable scene follows - it is Gilda's bawdy, sexy casino performance/glove striptease while singing the torchy, defiant number "Put the Blame on Mame, Boys." The lyrics of the song, filled with double entendres, describe a dangerous, threatening kind of woman who is often blamed - unfairly and illegitimately - by men. Instead of finding love in a spiritually-healing relationship with Johnny, Gilda finds herself caught in a complicated, hateful marriage. She fights back in the only way possible - with a defiant, drunken sexual exhibition that doubles as a self-fulfilling prophecy.

Swathed in a black satin dress displaying bare upper arms and shoulders, her dance is deliberately designed to shame, humiliate and infuriate Johnny in public. As she sings, she beckons with extended arms toward the lusting men in the audience and peels off one of her long, elbow-length black satin gloves - keeping the casino audience (and viewers) in suspense - wondering whether the strapless gown will remain suspended on her frame. Receiving accolades and encore-applause, Gilda flings her second glove toward the hungering audience. As she starts to shed her strapless dress, she entreats the men for assistance: "I'm not very good at zippers, but maybe if I had some help."

She is dragged away from the stage to prevent further embarrassment by Johnny's enforcer, and then in front of on-lookers, taunts Johnny:

Now they all know what I am, and that should make you happy, Johnny. It's no use just you knowing it, Johnny. Now they all know that the mighty Johnny Farrell got taken, and that he married a...

Johnny strikes her hard across the face.

Obregon continues speaking to Johnny in his office. He informs Johnny of the arrest of one of the agents of the Nazi-controlled cartel, knowing that "he will give us the information we want." Johnny refuses to turn over the incriminating patents and agreements that bear the signatures of the Nazi men. The signatures would prove their identity and guilt, and allow the police to legally prosecute them for "breaking the anti-trust laws." Obregon realizes that Johnny is more disturbed by the tumultuous love-hate relationship he shares with Gilda:

You two kids love each other pretty terribly, don't you?...It's the most curious love-hate pattern I've ever had the privilege of witnessing. And as long as you're as sick in the head as you are about her, you're not able to think about anything clearly.

Johnny is arrested for illegally operating a gambling casino and he is put under protective custody, while Obregon waits for him to turn over the patents with signatures: ("Send for me when you can't stand it anymore. I intend to have those signatures. I can out-wait you, Mr. Farrell. You see, I have the law on my side"). Under pressure, Johnny finally relinquishes the patents from the wall safe to the detective.

Obregon tells Johnny that Gilda is planning to return home to America from Buenos Aires. He offers Johnny a few more words of advice and suggests that he patch up his relationship:

At least you could do is say goodbye and wish her luck...How dumb can a man be? Do me a favor and get out of here before you realize what a heel you've been, will you, Mr. Farrell? I couldn't bear it to see you break down and feel like a human being. I'm a very sensitive man, for a cop. Gilda didn't do any of those things you've been losing sleep over - not any of them. It was just an act, every bit of it. And I'll give you credit. You were a great audience, Mr. Farrell.

The casino is closed down, the crowds are gone, and the rooms are dark. Uncle Pio (Steven Geray), the aging, white-coated washroom attendant of the casino's nightclub, offers Gilda a drink of whiskey as she sits on one of the barstools after hours in the "lonely" casino: "Would you like to have a tiny drink of ambrosia, suitable only for a goddess?" Gilda humbly refuses - she is wearing a traveling dress in readiness for her trip. Finally, Johnny realizes that he is really in love with her when he is about to lose her. He appears in a business suit and explains that he came to say goodbye.

In an upbeat finale, he finally admits how wrong he was and they reconcile with each other after many months of an explosive relationship:

Johnny: I want to go with you, Gilda. Please take me. I know I did everything wrong...
Gilda: Isn't it wonderful? Nobody has to apologize, because we were both such stinkers, weren't we? Isn't it wonderful?
Johnny: Wonderful.

At this crucial moment, however, when the two have rid themselves of the hatred that Mundson epitomized. Believed to be dead (after faking his own demise), he materializes again - the shutters on the mezzanine-level office mysteriously close after he has spied on them. He has returned after three months and now wants to re-establish his villainous supremacy over them: "...I want my wife." Black-clothed, he intends to kill Johnny with his dagger-cane for what he thought was Johnny's betrayal of him: "I thought it amusing to have one of my little friends kill the other. But now, it won't do." He lays the cane on the bar and chooses a gun as his weapon of choice because he must kill both Johnny and Gilda. As Mundson pulls out his gun to confront them and they back away slowly from him, Uncle Pio stabs Mundson with his own dagger-knife - Mundson dies impaled in the back with his own lethal sword.

Detective Obregon, in a conclusion vaguely similar to another early 40s film - Casablanca (1942), refuses to arrest the real killer when Johnny attempts to take the blame, lets everyone off the hook, drops the murder charges due to self-defense, and allows Gilda and Johnny to remain together. They finally receive their opportunity to settle their marital differences and put an end to Mundson's evil influence over them once and for all:

Obregon: You know, I'm a great cop, Mr. Farrell. I'm certainly a push-over for a love story... (To Uncle Pio and Johnny) You two can quit being noble any time you like, you know, because a man can only die once, and Mundson committed suicide three months ago. Besides, didn't you ever hear of a thing called justifiable homicide?
Gilda: Johnny, let's go home. Let's go home.