Feeling awkward in a beautiful white gown (with an evening cape decorated with sparkling beaded butterflies) after Jerry compliments her "striking impression" in the cocktail lounge, he lights another cigarette for her. She admits having borrowed Renee's ill-matched clothes (from which she has forgotten to un-pin tags and fashion notes) for the cruise: "This should pigeon-hole me for you alright...They don't suit me at all. In fact, they're perfectly ridiculous. You're quite right someone is playing a joke on me although it's far funnier than you realize." When Jerry introduces her to his old friends "Deb" McIntyre (Lee Patrick) and her husband Frank (James Rennie), he extends the masquerade further: "This is Camille Beauchamps." Later on the ship's deck, he explains his motives for falsely introducing her:

It was not to me to let the cat out of the bag. Did I do wrong?...It was the only French name I could think of, besides Vivi...My wife calls my lighter moments 'trying to be funny.' That's why I don't blame you for feeling the same way. But I intended a compliment. In that dress, you are rather like a camellia.

He realizes that she doesn't possess "a very high opinion" of herself. She describes the reason for her inferiority complex by showing him a picture of her disdainful, ancient-looking family. Their melodramatic, signature tune plays as their friendship grows beyond mere acquaintance and Charlotte begins to come out of her shell:

Jerry: (pointing at Charlotte in the picture) Who's the fat lady with the heavy brows and all the hair?
Charlotte: A spinster Aunt.
Jerry: Where are you? Taking the picture?
Charlotte: I'm the fat lady with the heavy brows and all the hair. I'm poor Aunt Charlotte and I've been ill. I've been in a sanitarium for three months and I'm not well yet. (She breaks down in tears) Forgive me.
Jerry: (at the railing) Feeling better?
Charlotte: Much. Thanks to you. Oh, many, many thanks to you.
Jerry: Thanks for what?
Charlotte: Oh, for sharing my carriage today and for walking my legs off sight-seeing. And for lunch and for shopping, and for helping me feel that there were a few moments when I - when I almost felt alive. Thank you.
Jerry: Thank you who?
Charlotte: Thank you, Jerry.

Charlotte sleeps fitfully that night. Having discovered that adults may retain loneliness from childhood and a wounded self-image, Jerry pens a letter to his daughter Tina, empathizing with her tears when he left home: "You were crying because you were being left alone. But today I made a discovery; all people are alone in some ways and some people are alone in all ways. Even after someone is grown up she can be alone."

On the deck while Jerry plays shuffleboard, 'Deb' McIntyre shares with Charlotte how Jerry has been trapped in his own life - with an unhappy, miserable marriage to an ailing, hypochondriacal wife that he doesn't love but cannot hurt, and with an un-'wanted' child:

...there's not much joy in life for him at home. Honestly, when I see what a woman like Isabel can do to a man like Jerry, it makes me boil...He's been cursed from the first day he met Isabel by a ruling passion not to hurt her...Isabel was one of those pure, high-minded girls who believed a kiss required a proposal of marriage. She's been about his neck ever since. Well, he struggled along with his architecture to get together enough money. Then he had to give it up. Only thing he ever loved. Isabel kept reminding him he was now a married man with financial responsibilities. And almost immediately she found she was going to have a child. She considered herself a great martyr and she's played the martyr ever since. That's her grasp on him - her martyrdom - and her jealousy...Mostly, she's jealous of Tina, the child she never wanted. Do you know that before Tina was born, Isabel actually went to a doctor and tried to get him to say her health wouldn't permit her to have a child? Yet, if you could hear her sanctimonious, maternal tone when she lets it leak out what a self-sacrificing mother she's been.

The pleasure cruise sails into the majestic Rio harbor, Jerry's "getting-off place." They hire a car and driver Giuseppe in Rio for sightseeing, but are badly shaken after their vehicle runs off a windy, mountainous road. When the driver leaves them to find help, the stranded couple seek overnight shelter in an abandoned cabin during a rainstorm:

Jerry: We're either going to have to bundle or freeze tonight?
Charlotte: They say that bundling is a New England custom both reverenced and honored.

During the night, Jerry rolls toward a sleeping Charlotte and kisses her - the scene fades to black.

The next morning, they discover that their ship has sailed on from the port without Charlotte, although she can rejoin the cruise in Buenos Aires: "There's a plane going down there first thing in the morning. There's another plane going down in five days. It'll get there the same day as your ship...It seems a shame to rush down there to spend five days alone." Jerry confesses he is "head-over-heels in love" with her - during a travelogue montage, they spend five amorous days together in Rio - sight-seeing, eating in restaurants, and dancing.

Above the strains of Steiner's romantic theme song, the couple speak on the moonlit balcony of their hotel - he entreats her to stay longer. In their famous scene together, cigarette smoking becomes more and more a sensual, shared, intimate act as he first performs the trick with her - and they kiss:

[The seductive two cigarette trick, a disguised metaphor for sex, in which Henreid places two cigarettes in his mouth, lights both of them, and then passes one to the expectant Davis, was first employed in The Rich Are Always With Us (1932) - ten years earlier.]

Jerry: Please, don't yet.
Charlotte: Well, I'm not going to struggle with you.
Jerry: That's right. No telling what sort of primitive instincts you might arouse. Isn't it beautiful? (He puts two cigarettes in his mouth, lights them both and then hands one to Charlotte.) Do you believe in immortality?
Charlotte: I don't know. Do you?
Jerry: I want to believe that there's a chance for such happiness to be carried on somehow somewhere.
Charlotte: Are you so happy then?
Jerry: Close to it. Getting warmer and warmer as we used to say as kids. Remember?
Charlotte: Look out or you'll get burned we used to say.
Jerry: Are you afraid of getting burnt if you get too close to happiness?
Charlotte: Mercy, no. I'm immune to happiness and therefore to burns.
Jerry: You weren't immune that night on the mountain.
Charlotte: Do you call that happiness?
Jerry: Only a small part. There are other kinds.
Charlotte: Such as?
Jerry: (As he speaks, he caresses her hand. Tears come to Charlotte's eyes) Having fun together, getting a kick out of simple little things, out of beauty like this. Sharing confidences we wouldn't share with anybody else in all the world. Charlotte, won't you be honest and tell me if you are happy too? Since the night on the boat when you told me about your illness, I-I can't get you out of my mind - or out of my heart either. If I were free, there would be only one thing I want to do - prove you're not immune to happiness. Would you want me to prove it Charlotte? Tell me you would. Then I'll go. (She turns toward him and buries her head in his chest.) Why darling, you are crying.
Charlotte: I'm such a fool, such an old fool. These are only tears of gratitude - an old maid's gratitude for the crumbs offered.
Jerry: Don't talk like that. (He takes her chin in his hand)
Charlotte: You see, no one ever called me darling before. (In close-up, they share their first mutual kiss - a passionate but gentle one.) Let me go. (They kiss a second time.)

At the Rio airport, Jerry says farewell with flowers. Charlotte has 'unbent' herself and grown into a sexually-mature woman during their transformative, star-crossed love affair. She and Jerry part in South America, believing that they might never see each other again - knowing that Jerry is married and won't desert his wife. In their famous departure scene, Jerry lights two more cigarettes and passes one to Charlotte:

Charlotte: I hate goodbyes.
Jerry: They don't matter. It's what's gone before.
Charlotte: No, it's what can't go after.
Jerry: We may see each other - sometime.
Charlotte: No, we promised. We are both to go home.
Jerry: Will it help you to know I'll miss you every moment?
Charlotte: So will I, Jerry, so will I. (Smoke curls up in front of them as they kiss goodbye.) Goodbye.

In the film's next section, Charlotte's cruise ship docks in New York City. While awaiting her arrival, Lisa and June discuss the 'old' Aunt Charlotte. To their complete astonishment, a sociable, outgoing 'new' Charlotte appears on the gangplank - wearing black in a medium-full shot: "Pinch me," they whisper to each other. The ship's tour director praises his most-popular passenger: "There was no lady on this cruise that was as popular as you were." A sleek, attractive and trim Charlotte teases her niece, calling her "rolly-polly." Feeling independent, confident, truly-loved, and with a restored sense of self-worth, a return to Boston later that afternoon anticipates a dramatic confrontation with her waiting, tight-lipped mother. Outside in the Vale driveway in Boston, Charlotte bolsters herself with a wish of luck from Lisa: "Wish me luck, Lisa." At the front door, she sardonically tells William (David Clyde), the butler:

Yes, William, it's me.

Charlotte ascends the stairs, hearing from a nurse-attendant Dora Pickford (Mary Wickes) that her elderly mother is "fit as a fiddle," but has an aging and fragile heart: "It'll last her for years if she doesn't get excited." The reunion scene with her mother is a classic confrontational scene. Charlotte is poised to open the door of her mother's room, but first hears Dr. Jaquith's advice in her head before entering:

Just remember that honoring one's parents is still a pretty good idea. You're gonna be a shock to her. I advise you to soften the blow. Give her time to get used to you. Remember that whatever she had done, she's your mother.

In her glamorous black outfit with a sweeping black hat, Charlotte strides in like a woman of the world. Her tyranically-hostile, disdainful mother, seated imperialistically at the far side of the room, surveys her crossing. Tension grips the air. Charlotte is commanded to obey her mother and then denounced - she is expected to resume her daughterly duties, and reside in her late father's room on the second floor:

Mrs. Vale: Step over there where I can see you. Turn around. Walk up and down. It's worse than Lisa led me to suppose. Much worse!
Charlotte: If you'd like me to go, Mother.
Mrs. Vale: Don't go. I have things to say to you. Sit down....Now that you're cured of whatever ailed you and have come home to take up your duties as a daughter again, I'll dismiss the last nurse...

Charlotte asserts herself and tries to liberate herself from her stifling, crippling maternal bonds, but her mother resurrects and opens old sores regarding Charlotte's forbidden, 'shameful' materials hidden in her room:

Charlotte: But Mother, you had no right to move my things.
Mrs. Vale: No right in my own house to move what I see fit? I'm not surprised you blush. I was in the room when William took the books from the shelves. And let me say that what we found hidden there was a very great shock to me. I can only hope that a shameful episode in your life is completely past.
Charlotte: If you'll excuse me, Mother.

At the door before leaving, Charlotte - with down-turned eyelids, is further ridiculed and victimized - and ordered to wear her old, ill-fitting dress, and remove her glasses and makeup for the evening's dinner party for relatives and family friends.

The maid delivers an air-expressed parcel from New York - a small corsage of camellias (for 'Camille') from Jerry. The lovers' identifiable theme music plays again.

In Charlotte's own room on the third floor, she is determined to battle her mother for independence. When her mother intrusively enters her room and demands for her to sleep on the second floor, Charlotte counter-argues: "Your guest prefers to sleep in this room - if you don't mind." With a self-assured manner, Charlotte leaves her mother's influential presence and defiantly addresses her from off-screen. The camera shoots the scene from behind Mrs. Vale's shoulder and hand (with tapping fingers) - outstretched on the vertical bedpost:

Charlotte: Mother - I don't want to be disagreeable or unkind. I've come home to live with you again here in the same house. But it can't be in the same way. I've been living my own life, making my own decisions for a long while now. It's impossible to go back to being treated like a child again. I don't think I'll do anything of importance that will displease you, but Mother, from now on, you must give me complete freedom, including deciding what I wear, where I sleep, what I read...Mother, please be fair and meet me halfway.
Mrs. Vale: They told me before you were born that my recompense to having a late child was the comfort the child would be to me in my old age, especially if she was a girl. And on your first day home after six month's absence, you behave like this.

As Mrs. Vale descends the stairs from Charlotte's room, she induces a fall halfway down - to engender pity and attention to herself. She recuperates in bed after being treated by a doctor for a painful torn ligament in her ankle and naturally, Charlotte feels accountable: "I feel responsible. We quarrelled." To the consternation and shock of the dinner party's guests, a stylishly-dressed Charlotte wears a fashionable dress she bought in New York City after the cruise - decoratively accented at the bustline with Jerry's white camellia corsage, a reminder that he once called her Camille. She is introduced to an eminent, wealthy Bostonian named Elliot Livingston (John Loder) who is interested in her as a suitor. As the guests leave after Charlotte's self-assured hosting, Lisa praises her: "I'm proud. Dr. Jaquith would be too."

But Charlotte's mother has been brooding about her daughter and her expensive dress - a symbol of increasing independence, throughout the entire evening. Charlotte gracefully listens to her mother's financial threats, but rather than loathing her or cringing under her strident demands, she quietly finds peace and realizes that she's no longer afraid:

Mrs. Vale: And you expect me to pay for articles charged to me of which I do not approve?
Charlotte: Well, I could pay for it myself. I have saved quite a little money. I have about five thousand dollars.
Mrs. Vale: Five thousand dollars won't last very long, especially if your monthly allowance were to be discontinued.
Charlotte: Oh. Mother, I want to ask you something. When father set up the trust for the two boys, why didn't he make one for me too?
Mrs. Vale: Because you were a mere child and he wisely left your affairs to my own better judgment. I'm sure you've always had everything in the world you want.
Charlotte: I haven't had independence.
Mrs. Vale: That's it. That's what I want to talk about - independence. To buy what you choose, to wear what you choose, sleep where you choose, independence. That's what you mean by it, isn't it?
Charlotte: Dr. Jaquith says that - that independence is reliance upon one's own will and judgment.
Mrs. Vale: I make the decisions here, Charlotte. I'm willing you should occupy your own room until I dismiss the nurse. She will occupy your father's room for the time being, and will perform a daughter's duties as well as a nurse's. That will give you a good chance to think over what I've said. I'm very glad to give a devoted daughter a home under my roof, and pay all her expenses, but not if she scorns my authority.
Charlotte: Well, I could earn my own living, Mother. As a matter of fact, I've often thought about it. I'd make a very good head waitress in a restaurant or...
Mrs. Vale: You may think that very funny, but I guess you'll be laughing out of the other side of your face if I did carry out my suggestion.
Charlotte: I don't think I would. I'm not afraid, Mother. (in close-up) I'm not afraid. I'm not afraid, Mother.
Mrs. Vale: Charlotte, sit down. I want you to know something I've never told you before. It's about my will. You'll be the most powerful and wealthy member of the Vale family - if I don't change my mind. I advise you to think it over.

Charlotte pens a letter that is intently read by Dr. Jaquith, detailing her "armed truce" relationship with her Mother and Elliott Livingston's proposal. Charlotte's voice-over presents the contents:

Dear Dr. Jaquith:

Summer, winter, now spring again. I won't say time flies but it doesn't crawl as it used to. Between mother and me, there is still an armed truce. She threatens but she doesn't act. I follow your advice. I stick by my guns but don't fire. There's a man here who's been nice to me, in fact he's proposed to me and there are no arguments I can think of why I shouldn't marry him. Most every woman wants a man of her own, a home of her own and a child of her own. His name is Elliott Livingston. He's from a fine Boston family and he's a fine man too, a widower with two half-grown sons. I don't know why I tell you this except I tell you almost everything.