At the platform of the Paris train station, they nervously search the crowd for a clue to identify the envoy. Without knowing the name or appearance of their comrade, they are surprised to find that she is a female. (They almost miss her because they don't expect the envoy to be a woman.) The no-nonsense, somber, humorless, severe and drably-clothed Soviet Nina Ivanovna Yakushova (aka "Ninotchka") (Greta Garbo) presents herself to her colleagues. When they are taken aback by the Envoy Extraordinary, she then unsmilingly cautions them to downplay her sexuality and not act gallantly:

Don't make an issue of my womanhood. We're here for work. All of us. Let's not waste any time. Shall we go?

The very capable female Soviet rigidly refuses to have a porter carry her bags:

Yakushova: Why should you carry other people's bags?
Porter: Well, that's my business, Madame.
Yakushova: That's no business. That's social injustice.
Porter: That depends on the tip.

She also brings news from Moscow, revealing her total dedication to the Communist cause [Lubitsch's joke pokes fun at the infamous Stalin trials]:

The last mass trials have been a great success. There are going to be fewer but better Russians.

In the hotel lobby, she observes a ladies hat in the showcase window of a hat shop and disparages the Western civilization that produced such a piece of merchandise: "How can such a civilization survive which permits their women to put things like that on their heads? (She shakes her head disapprovingly and dismissively turns away.) It won't be long now comrades."

When shown the tremendous hotel suite, she criticizes her frightened, horrified and harried comrades about the size and cost of her accommodations: "Which part of the room is mine?...If I stay here a week, I will cost the Russian people seven cows. Who am I to cost the Russian people seven cows?...(She loyally places a picture of Lenin on the desk.) I'm ashamed to put the picture of Lenin in a room like this." [Mocking Greta Garbo's well-known style from 1932's Grand Hotel], Iranoff asks:

Iranoff: Do you want to be alone, comrade?
Ninotchka: No.

Getting right down to business at a typewriter, Ninotchka discusses that their telegram was met with great disfavor in Moscow. She also wants to avoid repeating their mistakes: "I will have no dealings with the Grand Duchess nor her representative." After asking for cigarettes and noticing Iranoff's fancy spats, she suspects that her three comrades have been enjoyably leading the gay life in Paris and have betrayed the accomplishment of their mission. The sale of the jewels would provide funds to purchase farm equipment (tractors) to harvest crops for the financially-stricken homeland, but she believes that their 50/50 terms of settlement are unacceptable:

...at best, you have been careless in your duties to the State. You were trusted with more than the mere sale of jewelry. Why are we peddling our precious possessions to the world at this time? Our next year's crop is in danger and you know it. Unless we can get foreign currency to buy tractors, there will not be enough bread for our people and you comrades...50% to a so-called Grand Duchess. Half of every loaf of bread to our enemy!

Ninotchka orders her comrades to assist her - Kopalski is to go to the Russian Embassy and find the address of the best lawyer possible in Paris, Iranoff to the public library to research the civil code regarding property laws, and Buljanoff to find an accurate map of Paris. In her spare time, she plans to inspect the public utilities and to make a study of all outstanding technical achievements in Paris. Three well-trained cigarette girls interrupt their serious discussion, causing the three Russians to dip their heads guiltily. Ninotchka reprimands them: "Comrades, you must have been smoking alot."

Leon is ultimately foiled in his plan to corrupt the three Bolsheviks when he accidentally meets the stern Ninotchka on a traffic safety island waiting for the light to turn so they can cross the busy street. At first, he is unaware of her identity, even though she is his adversary. As she begins her inspection tour of the city, she is curious and asks him for statistical information:

Ninotchka: How long must we wait here?
Leon: Well, uh, until the policeman blows his whistle again.
Ninotchka: At what intervals does he whistle?
Leon: What?
Ninotchka: How many minutes between the first and second whistle?
Leon: You know that's very funny. I never thought of that before.
Ninotchka: You've never been caught in a similar situation?
Leon: Yes, I have, now that I've come to think about it. It's staggering. Good heavens. If I add it all up, I must have spent years waiting for signals. Imagine, an important part of my life wasted between whistles.
Ninotchka: In other words, you don't know.
Leon: No.
Ninotchka: Thank you.
Leon: You're welcome.

The suave and charming Count attempts to flirt with the entrancing woman, but realizes the daunting challenge he faces from the coldly humorless Muscovite. She asks him for assistance in holding her unfolded map of Paris, and discloses her destination is the Eiffel Tower to learn about it from a "technical standpoint." When she asks for directions, he takes her finger and points with it on the map, pointing first to the Tower's location and then to the hotel. In a no-nonsense, intelligent tone, she warns him about his flirtatious approach:

Ninotchka: You might hold this for me.
Leon: I'd love to.
Ninotchka: Correct me if I'm wrong. We are facing north, aren't we?
Leon: Facing north? Well now, I'd had to commit myself without my compass. Pardon me, are you an explorer?
Ninotchka: No, I am looking for the Eiffel Tower.
Leon: Good heavens, is that thing lost again? Oh, are you interested in a view?
Ninotchka: I'm interested in the Eiffel Tower from a technical standpoint.
Leon: Technical? No, no, I'm afraid I couldn't be of much help from that angle. You see, a Parisian only goes to the Tower in moments of despair to jump off.
Ninotchka: How long does it take a man to land?
Leon: Now isn't that too bad. The last time I jumped, I forgot to time it. Let me see now, the Eiffel Tower - ah, your finger please?
Ninotchka: Why do you need my finger?
Leon: It's bad manners to point with your own. (A close shot of the map with her finger pointing at it.) There, the Eiffel Tower.
Ninotchka: And where are we?
Leon: Where are we? Let me see. Where are we? Ah, here we are. There you are, and here am I. (She raises one eyebrow.) Feel it?
Ninotchka: I am interested only in the shortest distance between these two points. Must you flirt?
Leon: Well, I don't have to, but I find it natural.
Ninotchka: Suppress it!
Leon: I'll try. (She folds up her map.)
Ninotchka: For my own information, would you call your approach toward me typical of the local morale?
Leon: Mademoiselle, it is that approach which has made Paris what it is.
Ninotchka: You're very sure of yourself, aren't you?
Leon: Well, nothing's happened recently to shake my self-confidence.
Ninotchka: I have heard of the arrogant male in capitalistic society. It is having a superior earning power that makes you that way.
Leon: A Russian! I love Russians! Comrade. I've been fascinated by your Five-Year Plan for the last fifteen years.
Ninotchka: Your type will soon be extinct. (She walks out of the frame.)

At the entrance to the Eiffel Tower where Leon has accompanied her in a taxi, she asks about structural facts regarding the width of its foundation, its size, its steel composition, and the number of steps. Leon reads to her "valuable information" about its technical specifications from a guide book. She insists on walking up the 829 steps of the staircase (with an additional 254 to the very top) while he rides in the elevator. He calls out to her as she implacably proceeds to walk up a winding staircase to the top: "There's an elevator included in the price of admission. It'll take you hours to walk up there. The elevator will get you up in three minutes." When he reaches the highest platform of the Eiffel Tower, he is amazed to see her standing at the balustrade overlooking Paris - the City of Lights. It is the first visit for both of them. As they admire the beautiful, impressive night view from the Tower, she expresses her sorrow for his Western cultural roots:

Leon: I'm glad I saw it before becoming extinct.
Ninotchka: Now don't misunderstand me. I do not hold your frivolity against you. As basic material, you may not be bad. But you are the unfortunate product of a doomed culture. I feel very sorry for you.
Leon: Ah, but you must admit that this doomed old civilization sparkles. Look at it. It glitters!

At first, she is clinically cold, unromantic, and statistical, illustrated in her functional comments on Paris' sparkling, glittering beauty (its Grands Boulevards, the Arc de Triomphe, the Opera, Montparnasse, Montmartre, La Boheme) in their view: "I do not deny its beauty, but it's a waste of electricity." Then, he puts a franc in a telescope mounted on the tower, and has her view his "wonderful" and "charming" apartment - "the greatest attraction of all - the most unique spot in all Paris." While contemplating seducing her in his place, he describes what is so inviting and remarkable about his charming residence: "Well, it's not the structure. It's the spirit that dwells within it. It has three rooms and a kitchenette dedicated to hospitality." Not wishing to offend her, he invites her to accompany him to his house: "It's such a pleasant little place. It has all the comforts. Easy to reach - near the subway, bus, and streetcar." She accepts his invitation, rationalizing:

Ninotchka: Does it mean you want me to go there?
Leon: Oh, now please, please, don't misunderstand me.
Ninotchka: Then you don't want me to go there?
Leon: No, no, no, no! No, no, I didn't say that either. Naturally, nothing would please me more.
Ninotchka: Then why don't we go? You might be an interesting subject of study.
Leon: I'll do my best.

When they go back to his place, she introduces herself to Leon's elderly, dignified butler Gaston (Richard Carle) in the entrance hall. After expressing her concern for justice for the common man, she then promptly dismisses him with another echo of a famous remark:

Is this what you call the butler? ...Good evening, comrade. This man is very old. You shouldn't make him work...He looks sad. Do you whip him?...(She puts her hand on his shoulder.) The day will come when you'll be free. Go to bed, little father. We want to be alone.

In his art-deco style apartment, Leon removes her outer coat and cap while eyeing her sheer and revealing blouse. After putting on some background radio music, he persistently, slowly and gradually attempts to thaw and transform her Soviet rigidity, dogmatism, and literal coldness with romantic talk. First, he describes himself to her to assist her study of the decadent West. She responds with monotonous dullness in her voice, but then as they talk, she admits that she has sexual needs and instincts ("a natural impulse common to all"):

Leon: I'm thirty-five years old, just over six feet tall, and weigh 182 pounds stripped.
Ninotchka: What is your profession?
Leon: My profession? Mmmm, keeping my body fit, keeping my mind alert, and keeping the landlord appeased. That's a full time job.
Ninotchka: And what do you do for mankind?
Leon: For mankind? Yes, uh, not so much for mankind. But for womankind, my record isn't quite so bleak.
Ninotchka: You are something we do not have in Russia.
Leon: Thank you.
Ninotchka: That's why I believe in the future of my country.
Leon: Yes. I'm beginning to believe in it myself since I met you. I still don't quite know what it's all about. Confuses me, frightens me. It fascinates me. Ninotchka, you like me just a little bit?
Ninotchka: Your general appearance is not distasteful.
Leon: Thank you.
Ninotchka: The whites of your eyes are clear. Your cornea is excellent.
Leon: Your cornea is terrific. Ninotchka, tell me, you're so expert on things: can it be that I'm falling in love with you?
Ninotchka: Why must you bring in wrong values? Love is a romantic designation for a most ordinary biological - or, shall we say, chemical - process. A lot of nonsense is talked and written about it.
Leon: Oh I see. What do you use instead?
Ninotchka: I acknowledge the existence of a natural impulse common to all.
Leon: What can I possibly do to encourage such an impulse in you?
Ninotchka: You don't have to do a thing. Chemically, we're already quite sympathetic.
Leon (bewildered and intrigued): You're the most incredible creature I've ever met. Ninotchka. Ninotchka.
Ninotchka: You repeat yourself.
Leon: Yes, I'd like to say it a thousand times. You must forgive me when I seem a little old-fashioned. After all, I'm just a poor bourgeois.
Ninotchka: It's never too late to change. I used to belong to the petite bourgeoisie myself.

Ninotchka sits on the floor, leaning with her left elbow on the cushion of a large leather chair. As Leon sits forward and listens intently, he learns something of her background. Leaving her parent's farm - preferring "the bayonet" - she was a Sergeant in the Third Cavalry Brigade and wounded before Warsaw.

Ninotchka: My father and mother wanted me to stay and work on the farm, but I preferred the bayonet.
Leon: (repeating) The bayonet? Did you really?
Ninotchka: I was wounded before Warsaw.
Leon: Wounded? How?
Ninotchka: I was a sergeant in the Third Cavalry Brigade. Would you like to see my wound?
Leon: (with great enthusiasm) I'd love to.

She bends forward, bows her head, lifts her hair, and displays a wound behind her head in the nape of her neck, inflicted by the Polish lancer when she was sixteen. After sitting up again, she suggests that she doesn't need his pity. Her ineffable nature and beauty entrances him, and he falls victim to her (by understanding and learning about her passionate commitment to her ideals):

Ninotchka: A Polish lancer. I was sixteen.
Leon: (pitying) Poor Ninotchka. Poor, poor Ninotchka.
Ninotchka: Don't pity me. Pity the Polish lancer. After all, I'm still alive.
Leon: What kind of a girl are you anyway?
Ninotchka: Just what you see. A tiny cog in the great wheel of evolution.
Leon: You're the most adorable cog I've ever seen. Ninotchka, let me confess something. Never did I dream I could feel like this toward a sergeant. [A clock chimes midnight.]

While he romances her with love talk, she analytically rebukes him for trying to create a romantic mood with "forced sentimentality" to add to his exhilaration:

Leon: Do you hear that?
Ninotchka: It's twelve o'clock.
Leon: It's midnight. Look at the clock. One hand has met the other hand. They kiss. Isn't that wonderful?
Ninotchka: That's the way a clock works. What's wonderful about it?
Leon: Ninotchka, it's midnight. One half of Paris is making love to the other half.
Ninotchka: You merely feel you must put yourself in a romantic mood to add to your exhilaration.
Leon: I can't possibly think of any better reason.
Ninotchka: That's false sentimentality.

Then, Leon rushes to deliver a wonderful monologue about passion and love with an overwhelming desire for her:

Oh, you analyze everything out of existence. You'd analyze me out of existence, but I won't let you. Love isn't so simple, Ninotchka. Ninotchka, why do doves bill and coo? Why do snails, the coldest of all creatures, circle interminably around each other? Why do moths fly hundreds of miles to find their mates? Why do flowers slowly open their petals? Oh, Ninotchka, Ninotchka, surely you feel some slight symptom of the divine passion? A general warmth in the palms of your hands, a strange heaviness in your limbs, a burning of the lips that isn't thirst but something a thousand times more tantalizing, more exalting, than thirst

She ponders what he has said by looking intent and gazing into the faraway distance with a scientific attitude. With a side-long glance, she criticizes his talkativeness. Unable to contain himself, he plants a kiss on her lips - and she reciprocates:

Ninotchka: You are very talkative. (He kisses her.)
Leon: Was that talkative?
Ninotchka (with little feeling): No, that was restful. Again. (After being encouraged, Leon kisses her again.) Thank you. (She is leaning back on the leather chair)
Leon: Oh, my barbaric Ninotchka. My impossible, unromantic, statistical - (She takes charge and kisses him back.) Again.