Jerry Kingsley (March) is a widower in his mid-fifties. Jerry is well-to-do, owning his own garment business, which counts among its employees young Betty Prentiss (Novak). Jerry is lonely, two years having passed since his wife's death; in an early scene he calls up a woman he went out with some time ago only to find out she's gotten married again. Betty is lonely as well, her unhappy marriage having ended in divorce after her husband George left for a job in Las Vegas.
Jerry and Betty know each other only as work acquaintances, but one night when Jerry stops by Betty's apartment to pick up some documents, he finds her in emotional distress. Betty pours out her heart to her solicitous boss, telling Jerry that she's upset because her husband wants to come back and get back together. Jerry offers sympathy, and they bond. Soon they fall in love—much to the disgust of Jerry's daughter Lillian, who is actually a year older than Betty, and Jerry's sister Evelyn, who has assumed a sort of platonic wifely role in Jerry's life.
Martin Balsam appears as Jerry's son-in-law, Jack. One of only two movies Lee Grant (Betty's friend Marilyn) made between 1951 and 1963, as she had been put on The Hollywood Blacklist for refusing to testify against her husband for HUAC.
- Anguished Declaration of Love: Betty makes an early attempt to break it off with Jerry, citing the age difference and the fact that he's her boss. This forces an embarrassed Jerry to say straight out that he loves her.
- As You Know: Lockman, Jerry's gross partner, lets the audience know that Betty is divorced by saying "Now that you got that divorce from your husband, how about it?"
- Awful Wedded Life: We don't actually see it, as Mrs. Lockman never appears, but a despairing Lockman admits that he and his wife have been trapped in a loveless marriage for thirty years.
- Casanova Wannabe: Lockman eventually admits that he's making up the stories about his "tootsies", and has been impotent for the last two years.
- Daddy's Girl: Lillian, excessively so. Jack is visibly hurt when Lillian says no one's closer to her than her father, or when she tells him to butt out of an argument about Betty because "it's a family matter". Later Jack bursts forth with a "The Reason You Suck" Speech in which he rants about how sick he is of Lillian's overly close relationship to her father and how she needs to pay some attention to him for a change.
- Dirty Old Man: Lockman, who is something like 60 years old but is constantly talking about the chicks he's bagging, as well as hitting on Betty.
- Freudian Slip: Lillian thinks she's delivering a zinger to Aunt Evelyn, but she's actually being self-revealing.Lillian: Any man that gets close to my father I resent—I mean, you resent!
- Gray Rain of Depression: After Betty admits she cheated on Jerry and he breaks up with her.
- Insecure Love Interest: Jerry starts stressing out when the reality of marrying a spectacularly gorgeous woman 30 years his junior hits home.Jerry. I'm jealous. I'm afraid of every young man I see!
- Maiden Aunt: Evelyn. She says "I gave up my life" to look after Jerry and her other brother after their father died young. She is deeply threatened when Betty appears and is poised to assume the spousal role that Evelyn's been performing for Jerry.
- MayDecember Romance: Betty is 24, Jerry is 56, though during one of their arguments she exaggerates and tells him he's three times her age.
- Maybe Ever After: The story ends with Betty and Jerry getting back together, but all the issues that led them to split up before (the age difference, family disapproval, his jealousy, her insecurity) haven't gone away and will have a huge impact on the future of the relationship.
- New Year Has Come: Jerry gets very drunk at a party.
- Parental Sexuality Squick: Averted, as Jerry's daughter Lillian is utterly unashamed to ask questions like "Pa, how's your sex life?"
- Parent with New Paramour: Lillian struggles for a while after finding out that her father is getting remarried to a woman younger than she is.
- "The Reason You Suck" Speech: Regarding their relationship, Jerry gets a rather overly-dramatic one from Evelyn, while Betty gets a more down-to-earth one from Marilyn, both basically telling them that they're being too impulsive and that they're downplaying the age gap between them to a dangerous degree.
- Sex with the Ex: Betty makes a major mistake after George shows up at her apartment. Jerry is most upset.
- Sexy Discretion Shot: The camera cuts away as Jerry and Betty have a passionate embrace at the office.
- Sexy Secretary: Betty is a receptionist/office admin who also models clothes for Jerry's customers. Also, she is Kim Novak, so she's ridiculously good-looking.
- Shipper on Deck: Betty's family and friends try to push her toward reuniting with George.
- Sleeping Single: Despite being clearly established as lovers—Betty worries about getting pregnant—she and Jerry still stay in a cabin with two single beds.
- Snow Means Love: A weekend getaway to a resort up in the snowy mountains leads Betty to say for the first time that she loves Jerry.
- Sweater Girl: Kim Novak was dressed like this in pretty much every movie she made in the 1950s and this was no exception, as Betty wears flattering sweaters.
- Title Drop: Betty says that she's been waking up "in the middle of the night" because of her wedding jitters. And later she worries about how she'll be waking up Jerry in the middle of the night with her nightmares.