After a dissolve, they are dancing together. Their relationship soon blossoms, as they both have found someone that they can relate to. She has a spinster life similar to his - lonely, loveless, dull, and hopeless. Marty empathizes with her by admitting that he cries all the time - atypical behavior for a stocky male:

I cry a lot too. I'm a big crier...I cry all the time. Any little thing. All my brothers, my brothers-in-law - they're - they're always telling me what a good-hearted guy I am. You don't get to be good-hearted by accident. You get kicked around long enough, you get to be a - a real professor of pain. I know exactly how you feel.

He awkwardly attempts to make her feel better by telling her about his own rejections and ugliness ("Dogs like us, we ain't such dogs as we think we are"):

Marty: And I also want you to know that I'm having a very good time with you right now and really enjoyin' myself. You see, you're not such a dog as you think you are.
Clara: (smiling at his choice of words) I'm having a very good time too.
Marty: So there you are. So I guess I'm not such a dog as I think I am.
Clara: You're a very nice guy. I don't know why some girl hasn't grabbed you off long ago.
Marty: Well I don't know either. I think I'm a very nice guy. I also think I'm a pretty smart guy in my own way...You know how I figure. Two people get married and are gonna live together for forty or fifty years so it's gotta be more than whether they're just good-looking or not. Now you tell me you think you're not so good looking. Well, my father was a real ugly man but my mother adored him. She told me how she used to get so miserable sometimes - like everybody, you know? And, and she says my father always tried to understand. I used to see them sometimes when I was a kid sittin' in the living room talkin' and talkin'. And I used to adore my old man because he was always so kind. That's one of the most beautiful things I have in my life - the way my father and mother were. And my father was a real ugly man. So it doesn't matter if you look like a gorilla. You see, dogs like us, we ain't such dogs as we think we are.

A sub-plot is inter-cut with Marty's experience with Clara at the dance. His mother's widowed, fifty-six year old sister Catherine (Katarina) (Augusta Ciolli) is causing problems in the small apartment of her son Thomas (Tommy) (Jerry Paris), her daughter-in-law Virginia (Karen Steele), and their baby. Virginia begs Theresa to coax her mother-in-law into moving out and living with Theresa and Marty - without appearing to be cruel: "We'd thought you'd put it like - how you were lonely and why doesn't she come and live with you, because that way, it looks like she's doing you a favor instead of we're throwing her out, you know?" Sympathetic to the plight of Virginia and Thomas, Theresa speaks bluntly with her sister about leaving the young couple and coming to live with her: "Leave them in peace. He wants to be alone with his wife. They don't want no old woman sitting in the balcony." But Catherine refuses to give up her supportive role as wife, mother, and boss [in reality, she functions only as a cook and cleaner to serve her child] in her son's household - to face the uncertainties of widowhood and old age:

So I'm an old garbage bag put in the street, huh?...These are the worst years, I tell you. It's going to happen to you. I'm afraid to look in a mirror. I'm afraid I'm gonna see an old lady with white hair, just like the old ladies in the park with little bundles and black shawls waiting for the coffin. I'm fifty-six years old. And what am I gonna do with myself? I've got strength in my hands. I want to clean. I want to cook. I want to make dinner for my children. Am I an old dog to lay near the fire till my eyes close? These are terrible years, Theresa, terrible years...It's gonna happen to you. It's gonna happen to you! What are you gonna do if Marty gets married? Huh? What are you gonna cook? Where's all the children playing in all the rooms? Where's the noise? It's a curse to be a widow, a curse! What are you gonna do if Marty gets married? What are you gonna do?

Catherine's repeated warnings and her question: "What are you gonna do if Marty gets married?" stir up similar fears in her sister's mind. Theresa worries that the same loneliness will befall her when Marty considers marriage and vacates her house. Resigned to her situation, however, Catherine reluctantly agrees to move in with her sister the next day.

Marty and Clara spend many hours that first night talking and getting acquainted. He learns that she is an unmarried, twenty-nine year-old Brooklyn high school chemistry teacher. Marty begins to open up to her, telling her all about his past, his high school and army days, his family and his interests. As they leave the dance hall, he asks himself where all the seventeen years went since he graduated from high school: "Where did it all go? I'm getting old. I'm gonna be thirty-five years old November the 8th. Thirty-five! Wow! Time goes on, boy." He catches himself blabbering on, but continues talking anyway:

Marty: Boy, am I talking. I never talked so much in all my life...Well, I'm gonna shut-up now and let you get a word in. Yeah, seventeen years ago. What have I been doing with myself all that time? Well, there I go again. I must be driving you crazy. Most of the time when I'm with a girl I can't find a word to say. Well, I'm gonna shut up now and let you get a word in...There I go again. I can't stop talkin'. I'm on a jag for Pete's sakes. You'd think I was loaded...I can't stop my mouth! Isn't this stupid? (He compliments her.) You got a real nice face, you know. Really a nice face.
Clara: Thank you.

At a small luncheonette where they talk over coffee, they continue their conversation for three more hours and become even better acquainted. Marty shares with her his hesitant thoughts about his life's longings, hopes, and dreams - he plans to buy the butcher shop where he works ("It means I gotta take a loan out from the bank for $8,000 dollars. That's a big note to carry"). After knowing him for only a short time, she encourages him to pursue his wishes:

...I know you're a good butcher. You're an intelligent, decent, sensitive man - and well, I have a feeling about you. Like, well, sometimes one of my kids comes in to see me about something or other, and some of these kids who aren't in my classes, they-they have so much warmth and so much capacity. Well, that's the feeling I have about you. If you were one of my students, I would say to you, 'Go ahead and buy the butcher shop. You're a good butcher.'..I think anything you'll do, you'll want to do well.

Angie searches around the old haunts for Marty, and happens to listen in on bar-room gossip between two older women. The "sad story" is about a younger woman who defied her doctor's advice about having a seventh baby and ultimately died during childbirth - it reflects the film's attitude toward sacrificial motherhood:

She told me that the doctor told her if she had any more babies, she'd do it at the risk of her life. When she told me that she already had six, every time I saw the woman, she was either going to the hospital or coming from it. She was hatching them out like eggs....Well, I bumped into her on the street and she was as big as a barrel. And I said to her, '...didn't you tell me that if you had another one it would kill you?'...Well, last week on Tuesday, she gave birth to her baby in St. Elizabeth's Hospital. A fine healthy boy. Nine pounds...She died right there in the hospital.

While walking together back to his house to "pick up some dough" at a quarter to twelve, Marty advises Clara about going out on her own, becoming independent from her parents, and taking the risk (and opportunity) of accepting a job in Port Chester (New York) as the head of a science department. He expresses his confidence in her thought of moving away from her parents' home:

Marty: Well, let me tell you, Clara. I think you're kiddin' yourself. I mean, I used to think about leaving home, you know, and that's what I used to say: 'My mother needs me.' But, when you really come down to it, that ain't it at all. We're just afraid to go out on our own. I - I mean, it's a big step when you go out on your own. And, well, I think you're kiddin' yourself when you say your father needs you. Actually, you need your father. You know what I mean? Well, you know what I mean. You're living at home now, and you got your father and mother there, and you can go on like that, being a little girl, all your life.
Clara: I'm afraid of being lonely.
Marty: You won't be so lonely. You'll make friends right away.
Clara: Actually, I don't make friends easily.
Marty: Well, what are ya talkin' about? You're a real likeable person. You make friends up there in Port Chester one, two, three. You'll have people visitin' ya all the time. Oh, I'll come up and visit ya...It'll be real nice. Don't be so afraid.

Ralph (Frank Sutton) and Leo (sitting in a parked car) - two friends of Marty's - attempt to persuade him to dump Clara and join them and three nurses for a sure transaction - sexual fulfillment ("Money in the bank, man...This is a good deal here, Marty"). He honorably declines to desert his newfound friend. After midnight, when he takes her home to meet his mother and she isn't there, Clara looks uncomfortable and tense. So Marty helps her put her coat on to leave and suddenly attempts to kiss her. He is rebuffed momentarily - and then reassured that Clara wants to see him again:

Clara: No, Marty, please.
Marty: I like ya. I like ya. I've been tellin' ya all night I like ya.
Clara (surprised): Marty. (She turns away.)
Marty: All I wants is a little kiss.
Clara: No.
Marty: Please?
Clara: No.
Marty: Please.
Clara: No, Marty.
Marty: (His feelings hurt.) All right, all right, I'll take ya home. All I wanted was a lousy kiss. You think I was gonna try something serious with my mother comin' home any minute?
Clara: I just didn't feel like it, that's all.
Marty: Well, I'm old enough to know better. Comes New Year's Eve, everybody starts arranging parties. I'm the guy they got to dig up a date for...
Clara: (soothing his feelings) I'd like to see you again - very much. The reason I didn't let you kiss me was because I just didn't know how to handle the situation. You're the kindest man I ever met. The reason I tell you this is because I want to see you again - very much. I know that when you take me home I'm just going to lie on my bed and think about you. I want very much to see you again.
Marty: What are you doin' tomorrow night?
Clara: Nothing.
Marty: I'll call you up tomorrow. Maybe we'll go see a movie.
Clara: I'd like that - very much.
Marty: The reason I can't be more definite now is, is because my Aunt Catherine's probably comin' over tomorrow. I may have to help out.
Clara: I'll wait for your call.

And then as they prepare to leave the house, he asks her about her New Year's Eve plans as they stand face to face with each other:

Marty: What are you doin' New Year's Eve?
Clara: Nothing.

In a tender, memorable moment, they kiss and hug each other. In the middle of their embrace, the sound of a door closing interrupts them. Marty's mother arrives home and is introduced to Clara ("a graduate of New York University"), and then immediately recounts how her widowed sister doesn't get along with her daughter-in-law Virginia and will come to live with them. She shows some worry about the first girl that Marty has brought home in a long time and the impact of losing her influence over him. Mrs. Pilletti laments being left alone, like her sister, with nothing to do but wait for death:

Mrs. Pilletti: ...a woman, fifty-six years old - all her life she had her own house. Now, she's just an old woman sleeping on her daughter-in-law's couch. It's a curse to be a mother, I tell you. Your children grow up and then, what is left for you to do? What is a mother's life but her children? It's a very sad thing when your son has no place for you in his house.
Clara: Couldn't she find some kind of hobby to fill out her time?
Mrs. Pilletti: Hobby, hobby! What can she do? She cook and she clean - but you gotta have a house to clean. You gotta have children to cook for. These are the terrible years for a mother.

Without wanting to get involved, Clara advises Mrs. Piletti: "You mustn't feel too harshly against your daughter-in-law. She probably also wants to have a house to clean and children to cook for...As a rule, I don't think a mother-in-law should live with a young couple...Well, I don't think a mother should depend so much upon her children for her rewards in life." Marty's mother makes a snide comment that was critical of Clara:

Well, that's what they teach you in New York University? In real life, it no work out like this. You wait until you are a mother.

After they disagree about where a mother-in-law should live, Marty interrupts their conversation and urges that Clara should be taken home because it's late.

When they run into his best friend Angie along the way, he acts "sore" for having been left alone at the ballroom. He also behaves jealously as if he thinks Clara is a rival for his friendship. He storms off after his offer to ride the bus with them is rejected:

Angie: What are we gonna do now?
Marty: I'm gonna take Clara home. It's close to one.
Angie: You want me to ride down with ya?
Marty: What for?
Angie: It's early.
Marty: It must be one o'clock.
Angie: It's Saturday night. There's still plenty action around.
Marty: Well, listen Angie, by the time I get Clara home, it's gonna be one, one-thirty, and by the time I get home, it's gonna be two o'clock. I gotta get up for ten o'clock mass tomorrow.
Angie: (sore and dejected) OK, I'll see ya.

In front of her house as he says goodnight to Clara, Marty promises to call her to confirm a date for the following evening. Exuberant, Marty hails a taxi to take him home.

The next morning before Sunday mass, Marty is bubbling over with joy over his new-found love - and he is optimistic about buying the butcher shop. Tommy, Marty's married cousin, who delivers Aunt Catherine to live with Theresa, has just had a bitter fight with his wife over deporting his mother. He is tormented by guilt feelings, although his wife has persisted in her belief that they run their own household: "We're never gonna be happy unless we have a chance to work out our own lives...We gotta have some privacy." On the porch before leaving for Mass, Tommy tells Marty that being a husband and a father bring only extra responsibilities and burdens. He envies Marty's single independence "with no responsibilities" and warns him about wanting to take on extra duties or responsibilities (such as owning a butcher shop or getting married):

What do you want to buy a shop for? Will you tell me? You got a good job. You got no wife. You got no responsibilities. Boy, I wish I was you, boy...For Pete's sake, you're a single man with no responsibilities. Stay that way, boy, take my advice!

[During early morning coffee, Mrs. Pilletti and her sister - two middle-aged Italian widows, talk about the idleness that threatens the remainder of their lives. Theresa hears more frightening predictions from Catherine about losing her house: "You'll see. Today, tomorrow, in a week, he's gonna say to you, 'Hey, Ma. I'm tired of running around. It's no good to be a single man.' Then he's gonna say to you, 'Hey, Ma. Why do we need this old house? Why don't we sell this old house and move into a nicer part of town, a nicer little apartment...' You'll see. In a couple of months, you're gonna be an old lady sleeping on a couch in your daughter-in-law's house."]

On the church steps before Mass, Marty's protective mother asks pointed questions of Marty about the new girl he has feelings for. Fearing the loss of her son when Marty marries - and feeling threatened, she delivers a diatribe against Clara's old age, her homeliness, her improper and 'unchaperoned' house visit, her "college-graduate" intellectualism, and her non-Italian heritage. In her opinion, Clara is definitely not his type at all:

Mrs. Pilletti: She wasn't a very good looking girl but she looked like a nice girl...not pretty. She look a little bit old for you. About thirty-five, forty years old?
Marty: She's twenty-nine, Ma.
Mrs. Pilletti: She's more than twenty-nine years old, Marty. That's what she tells you...She looked thirty-five, forty years old. She don't look like an Italian girl...What family she comes from? I don't know. Something about her I-I don't like...The first time you meet the girl, she comes to your empty house alone. These college girls. They're only one step from the street.
Marty: What are ya talkin' about? She's a nice girl.
Mrs. Pilletti: She don't look Italian to me. I don't like her...Don't bring her up to the house no more.

Marty also has to defend Clara to the local luncheonette bartender, and to Angie and his friends who come over to his house to visit. His pals idolize writer Mickey Spillane's (who "can really write") paperbacks [the hero of his pulp novels is Mike Hammer who "knows how to handle women"] and read men's magazines such as Girls and Gags. They disdain Clara's appearance and call her "a dog," because she doesn't fit the female ideal found in their fantasy worlds:

Angie: She must have been about fifty years old.
One of Angie's friends: You know the way I figure, a guy ought to marry a girl twenty years younger than he is, so when he's forty, she's still a real pretty doll of twenty-one.
Jerry: That means he'd have to marry the girl when she was one year old.
One of Angie's friends: You know you're right. I never thought of that.
Marty: I didn't think she was so bad looking.
Angie: Well, she must have kept you in the shadows all night.
One of Angie's friends: Marty, you don't want to hang around with dogs. It gives you a bad reputation.
Angie: Let's go down to 72nd Street.
Marty: I told this dog I'd call her up today about two-thirty.
Angie: Pressure. Listen, you want to come with me tonight, or you wanna go with that dog?
Marty: What are ya gettin' so sore about?
Angie: Because I looked all over for you last night. You know that?

Doubts begin to enter Marty's mind following everyone's negative reactions to Clara. Intimidated by the influential people in his life, Marty ends up back in the same dreary patterns and conversations that he has had for so many years with his neighborhood pals and his mother. He doesn't call Clara as he had promised in the afternoon, leaving her to sadly sit at home (with tears on her cheeks) watching TV (The Ed Sullivan Show) with her parents - sensing that her phone may never ring. Likewise, he agonizes over ignoring a girl who has profoundly touched him.

Later that Sunday evening as he and his pals pass the time outside the local bar, he hears his friends repeating the same old boring, nihilistic refrain:

'What do you feel like doing, Angie?'
'I dunno. What do you feel like doing?'
'I dunno.'

Suddenly, Marty mimicks the same old conversation:

'What are you doing tonight?' 'I dunno. What are you doing tonight?' The burlesque. Loew's Paradise. Miserable and lonely. Miserable and lonely and stupid! What am I, crazy or something? I got something good here. What am I hanging around with you guys for?

Marty is asked by Angie and his friends what is wrong. Marty tells his buddies how he genuinely feels about Clara. Refusing to be a social outcast any longer, he courageously and defiantly rises up against them:

You don't like her. My mother don't like her. She's a dog. And I'm a fat, ugly man. Well, all I know is I had a good time last night. I'm gonna have a good time tonight. If we have enough good times together, I'm gonna get down on my knees. I'm gonna beg that girl to marry me. If we make a party on New Year's, I got a date for that party. You don't like her? That's too bad.

Awakening to his own reality of thirty-four years of loneliness, Marty abandons his friends and family and calls Clara from a pay phone in a booth. After dialing, he turns toward Angie and asks: "Hey Ange, when are you gonna get married? You oughta be ashamed of yourself. You're thirty-three years old and your kid brothers are married. You oughta be ashamed of yourself."

Marty excuses himself and shuts the phone booth's door. In the last line of the film, he speaks to Clara:

"Hello...Hello, Clara?"