Sam orders a double-stout, and meets the seasoned, self-assured female traveler reclining on a deck chair. He admits that it is his first trip to Europe. He explains what his wife (and he) are after. They have a prescient discussion of Sam's future goals and objectives in a six-month, self-appointed program of broadening and 'educating' his life and soul with new experiences. Without pretense, she appreciates Dodsworth's curiosity and hunger for adventure in a refreshing way:

Sam: She wants me to learn how to enjoy my leisure, now that I'm retired. But what it boils down to - well, I've been doing things myself for a long time now. I thought I'd give things a chance to do something to me.
Edith: The education of an American.
Sam: Yes, you might call it that.
Edith: How long have you given yourself?
Sam: Six months.
Edith: To get all that done?
Sam: Oh, I'll be homesick by then.

Edith explains that she is from Michigan, and "used to be a British subject by marriage." Now she lives in Italy as a divorcee, because it's "cheap."

Meanwhile, Lockert is offering a nightcap to Fran in her stateroom, when she suggestively wishes: "I'd like to stay right here and see the dawn." When he is curious whether Sam will be jealous of them for their risky behavior, the eager and receptive Fran is reassuring: "He's got all the old-fashioned values, except jealousy." She encourages lothario Lockert to show interest in her attractiveness.

At the same time, Sam has ushered Edith to the bar for highballs, where she formally introduces herself as Mrs. Edith Cortright (veteran actress Mary Astor), an attractive, kind, young and sensitive woman, who is drifting from place to place. She describes her tendency as a lone woman to go "drifting" - "One drifts for lack of a reason to do anything else." He explains his own situation to her. Although he enjoys traveling abroad for awhile, he prefers a predictable and steady life back in America:

When a man has no more job and his wife wants a fling, there are worse things than travel.

At the rail of Fran's stateroom in the romantic moonlight, Lockert encourages Fran to remain in London (with him) rather than trek all over the continent with Sam. Increasingly dependent on the attentions of a man other than her husband, she enjoys his loving words (Lockert: "I should miss you so terribly") and allows him to kiss her. She naively leads him on - then is quickly offended as she breaks away and turns down his sexual advances: "That's a very silly thing to do. I don't think I like it." She rejects his invitation for lunch the next day in London, and bids him a brief goodnight. He complains about her harsh treatment of his "innocent flirtation," and then apologizes for his behavior, although he then chastizes her for tempting him and critically insults her for thinking of herself as a cosmopolitan, sophisticated woman of the world:

You're taking a wickedly unfair advantage of me. I only thought I was doing what was expected of me...For a civilized woman who's been married as long as you have, you're making a great deal of a small matter...I offer you my most abject apology. If I might offer you one small word of advice, give up starting the things you're not prepared to finish. It's quite evident that they only lead you out of your depth...Any modern schoolgirl could compete with this situation. You know, you destroy me with the most childish misconception of yourself. You think you're a woman of the world, and you're nothing of the sort.

Sam returns - and characteristically down-to-earth, he calmly believes that Lockert is only harmlessly "fresh" after being asked to leave their room. Fran confides in Sam and begins crying, claiming that she is furious at "rotter" Lockert for insulting her, but she really feels frustrated and humiliated by the situation. Sam jokes and then asserts that she has been flaunting conventional behavior: "It's your own fault for leading him on...You must have given him some excuse. You have been flirting with him." She takes offense when he seems to blame her: "I've always been loyal to you. You'll be sorry for this." Then, Fran impulsively urges Sam to skip England and immediately accompany her to France, to avoid Lockert: "I can't stay in England with that man laughing at me...", and then cozies up to her husband, fearing as a midwestern American 'hick' that she could never keep up with the cosmopolitan socialites in Europe:

You've got to take care of me. You really have, Sam. I don't trust myself. I'm afraid of myself...I'm just a wooly American like you after all. And if you ever catch me trying to be anything else, will you beat me?

In Paris after a few weeks, Sam is still thrilled by the traditional tourist sites - the obelisk where the guillotine was located that cut off Marie Antoinette's head, and where Madam Roland was significantly quoted as saying: "Oh Liberty! What crimes are committed in thy name!" Their sight-seeing European ventures are largely taken separately, however. Today with his guidebook, he is planning to see Napoleon's tomb, while she has a late morning fitting and hairdresser's appointment, and an afternoon at the Ritz with socialite Madame Renée De Penable (Odette Myrtil). She has been able to successfully hide her background and flaunt herself as a high-society denizen (supported by well-to-do Sam's funding), while associating her stable, secure, unchanging husband with old age and 'hicks'.

During tea, Fran is introduced to international financier and distinguished art collector Arnold Iselin (Paul Lukas), who compliments her as "charming." At 4 pm, Sam is predictably stood up by Fran at the Cafe de la Paix, a sidewalk cafe for commoners. Meanwhile, she is being courted in fancier more refined surroundings by the predatory Iselin: "What can I do to find myself a part of your Paris?" She invites him for dinner the following evening.

Fran celebrates her birthday with guests including Mrs. Cortright, Iselin, and young Austrian Baron Kurt Von Obersdorf (Gregory Gaye). Unimaginative and dull Sam had opted for a formal dinner rather than a nightclub experience. As Renée leaves for the evening, Edith and Fran have a telling conversation about her age - something that Fran continually lies about:

Edith: I hadn't realized it was your birthday.
Fran: No? Wish I hadn't. No woman enjoys getting to be 35.
Edith: When you're my age, you look back on 35 as a most agreeable time of life.
Fran: I hope I look as young as you do when I'm your age.
Edith: You're almost sure to, my dear.

Fran sets up another dinner date with Iselin, the following Tuesday at 8:00 pm at his residence, the Quai Voltaire. Edith is off to Italy (near Naples) the next morning - but before leaving, she cautions Fran about her obvious intentions to have an affair with Iselin: "My dear, don't."

In their hotel room after the guests depart, Sam suggests that they've been away from home long enough, and should plan on reserving an August sailing: "Don't you think it's about time we're beating it back home?", although Fran wants to see much more of Europe. Believing that her embarrassing midwestern "hick" husband Sam is overly dull and unadventurous, she craves excitement by remaining longer in Paris with her "really nice friends" at expensive restaurants, and seeking reassurances from distinguished men. Sam rethinks things and tends to agree, for other reasons - he anticipates many more exciting sightseeing tours - in the Mediterranean, Germany, and Italy (Venice and Rome).

Then as they get ready for bed (and she applies cold cream to her aging face), feigning selflessness, she proposes: "Why don't you go home?...Get yourself a new lease on life and come back here and join me." Startled, he refuses to leave without her, and states that he dislikes most of her newly-acquired continental friends. He considers them mostly "moochers": "I don't think they're so nice. I don't, and I don't see what you see in them." She ridicules his unimpressive, bourgeois tendencies while assuming affectations of culture herself. She vehemently disagrees with him and sides with her latest high-class acquaintances:

They all belong to the smartest crowd in Paris...You may be the most impressive man in Zenith, Sam, but you're not in Zenith now. You're in Paris now, and I'm tired and sick of apologizing to my friends.

She desires the refinements of Europe, not Zenith, and snaps at Sam, while he retorts back. Eventually, she announces splitting from him for the remainder of the summer:

Fran: Oh, you're hopeless. You haven't the mistiest notion of civilization here.
Sam: Yeah, well, maybe I don't think so much of it, though. Maybe clean hospitals, concrete highways, and no soldiers along the Canadian border come near my idea of civilization. There are 20 million automobiles in America. Now, I've contributed something to every single one of them from my own personal civilization. And if that isn't more than knowing how to order dinner as your friend the madam...
Fran: You don't want to learn. I could teach you. I belong here. They accept me here.
Sam: Yeah? Well, I'm gonna get out of this town and back to doing something, and take you along.
Fran: Well, I'm not going, Sam.
Sam: Oh, yes, you are.
Fran: No, I'm not. I think you and I need a vacation from each other.
Sam: Well, I don't feel that way about it. I think I've been weak with you long enough.
Fran: Besides, I've rented a villa with Renee for the summer at Montreux on Lake Geneva in Switzerland. I've signed the lease.
Sam: Well, I think you might have told me.
Fran: I got my own money.

When he caves in and decides to remain in Europe with her, to wait out her restless mid-life crisis, she devastates him by demanding a trial separation for the summer, so that she can have a youthful fling:

Sam: Fran, my darling, you're not drifting away from me.
Fran: I hope not.
Sam: Oh, no. You and I, Fran, after all these years. All right, I'll give it up. I won't go home.
Fran: But, you've, you've got to go home. You've simply got to. I can't stand being torn like this any longer. Oh, I'm sorry for all the mean things I've said to you. But if you and I are gonna go on together, you've simply got to let me alone this summer. Oh, don't look so hurt, and please don't be angry. Oh, be as angry as you like, if it does any good! Remember, I, I did make a home for you once, and I'll do it again, only you've got to let me have my fling now! Because you're simply rushing at old age, Sam, and I'm not ready for that yet.

Sam decides to immediately leave for home, and returns to Zenith on the next boat to the US. Upon his arrival, he vaguely explains to his daughter Emily why Fran is still in Europe: "She's got some things she wants to attend to." Fran is already involved in an affair with Arnold Iselin at her rented villa with Renee on Lake Geneva and at Iselin's place, and also fawned over by Kurt von Obersdorf. A letter from Sam back home immediately depresses Fran: "I've been having such fun today. This letter's spoiled everything. Switzerland, the lake, the house. All of it's just so much Zenith now." She feels tortured when she contemplates an inevitable return to Zenith. When Iselin proposes "making love" to her, she draws back slightly and affirms that she has always been able to trust Sam, even though he isn't always as attentive and loving. Iselin suggests living in the present (the letter represents her past and future) by setting fire to the letter, which is then let go and sent blowing across the terrace.

Back in Zenith, crotchety and grouchy Sam realizes that he is missing Fran, and her habitual ways of displaying his mail on his desk and having his whiskey/soda/ice waiting for him, and he complains about the humidor missing from a library table. Emily apologizes: "I'm sorry things aren't the way they used to be, but Harry and I are living in this house too." Sam is expecting Fran to return soon, and Emily excuses herself for suspecting that there was "trouble" between the two of them when he first came home.

However, a cable from Fran causes a stony and grim response from Sam. Fran is not coming ("Want two more months Europe. Hope you having good time home"), and he thinks: "It's lonesome here without her...I cable her to come and she doesn't say one word about me going over." He believes she is scared of growing old. In her last letter, Fran said that her group was having a good time with her European friends, including Arnold Iselin. Sam decides to return to Europe - he dictates a cable to be sent to Mrs. Dodsworth:

Sailing Aquitania Wednesday. Stop. Meet me Creon, Paris. Love, Signed, Sam.