Plot

An obese, embittered nurse doesn't mind if her toupee-wearing boyfriend romances and fleeces other women, as long as he takes her along on his con jobs.

In the early 1950s, Martha Beck, who lives with her slightly senile mother, is the head nurse in a Mobile, Alabama hospital. She is bitter about her life, she not having male companionship in large part because she is overweight, while her bitterness in turn does not endear her to people. She is initially angry with her best friend, Bunny, for signing her up to a lonely hearts club, but eventually decides to give it a try. Through it, she meets Ray Fernandez, a suave Spanish immigrant living in New York, he who contacted Martha as the first through the club. After Ray's trip to Mobile to meet Martha, they fall in love. Upon a subsequent visit Martha makes to Ray in New York - which leads to her being fired in part for her time off work - he decides to be up front with her: that she is not only not his "first" but that he is really a con man who, primarily through the club, seduces then bilks lonely women of their money. Pretending to be his sister to prospective targets, Martha decides to join Ray on his cons as they travel the country together. Their differences in style causes problems, Martha who is more direct, more impatient and more violent, she who is the first to consider killing to get what they want. But what has the potential to be the primary cause of their downfall is Martha's jealousy over Ray even pretending to seduce other women, let alone any time he may have sex with them.—Huggo

Based on the true story of Raymond Fernandez and Martha Beck, who met through a lonely-hearts correspondence club. Ray is weedy, feral, and untrustworthy; Martha is enormous, compulsive, and needy. Together, they play out a horrifying scheme in which he lures lonely women out on dates and proposes marriage to them, with her pretending to be his sister. They take the women's savings and then murder them remorselessly. Dank, claustrophobic, and weirdly engrossing, this movie never quite gives in to the comforts of conventional narrative. Francois Truffaut named it as his favorite American film.—alfiehitchie

The film opens by introducing Martha Beck (Shirley Stoler), a supervising nurse in a hospital that is said to be in Mobile, Alabama. Martha catches two underlings having a brief romantic interlude in one of the labs and berates them for doing so. Martha is bitter and vindictive; she is overweight and lonely, lashing out at those who are unlucky enough to be under her command at the hospital, while at home she is saddled with an elderly mother (Dortha Duckworth) who still calls Martha her "little girl". Martha's best friend, Bunny (Doris Roberts), surprises Martha by sending for an application to a lonely hearts club, thinking that all Martha needs to be happy is a man.

At first Martha is resentful that Bunny has done this, but soon she is corresponding with a suave man named Raymond Fernandez (Tony Lo Bianco). Raymond gives Martha a vague representation of his life in New York, and comes to visit her after many weeks of exchanging letters. Martha is smitten with the handsome Ray, and their relationship immediately turns sexual. In a bizarre twist, Martha gives her mother a sleeping pill so that she and Raymond can be alone, then the two of them share a sexual encounter while her mother sleeps nearby on the couch.

When Raymond returns to New York, he borrows a small "loan" from Martha, then sends her a telegram from New York saying that he can no longer correspond with her. Martha is despondent and enlists Bunny's help in pulling an extreme stunt: she tells Raymond that she has attempted suicide because she cannot live without him. Raymond seems flattered by Martha's devotion and invites her to New York, where he makes a startling revelation to her: he is actually a con man who meets lonely women through various lonely hearts clubs, then takes them for as much money and valuables as he can. After meeting Martha he realized she had no assets and moved on, but Martha is willing to forgive him for his deception. Raymond seems to be interested in Martha's strange devotion to him, and he tells her one day he will marry her for real.

When Martha returns home to Mobile, she finds that her supervisor has uncovered some torrid correspondence with Ray that Martha had stored in her desk. Martha lashes out at him bitterly and resigns, claiming that she went to New York to be married and her final check can be made out to Mrs. Ray Fernandez. At home, Martha continues the charade, telling her mother and Bunny that she and Raymond have been married. Raymond is furious, especially when he realizes that Martha intends to bring her mother along with her to New York to move in with Ray. Raymond forbids it, saying that Martha can come but she absolutely cannot bring her mother, even going so far as to tell Martha to "put a pillow over her face" to get rid of her. Instead, Martha puts her mother in a rest home and abandons her, even though she weeps and pleads with Martha to take her along. Finally the woman curses Martha as she leaves, leaning out of a window and shouting after her "Goddamn you! I hope you end up like this! I hope someone does this to you."

Martha and Raymond immediately begin their new business of swindling lonely women out of their savings, starting with a spinster schoolteacher. Raymond tells her that Martha is his "sister", and Martha accompanies them on their honeymoon, but Martha takes the new bride's belongings the first night and the bride storms out in a fury. Martha pays her no mind, threatening to expose the woman's torrid correspondence with Raymond to her superintendent.

Martha seems to have no problem handling this first victim, who is unattractive and mawkish. But she remains hesitant about Raymond's "profession", jealous that he may choose a more attractive woman to swindle and make love to her. Their next mark proves to be a little different. Myrtle Young (Marilyn Chris) is a spunky Southern woman who makes no secret about her attraction to Raymond. She has hired Raymond in a business transaction; Myrtle is pregnant out of wedlock, and she wants Raymond to pose as her husband to save face for her family. However, when she finds Raymond handsome, she turns on the charm, much to Martha's jealous displeasure. When Myrtle buys Raymond a toupee as his wedding gift, Martha scoffs at it, but Raymond lies and tells Martha that he bought it for himself. Myrtle later sneaks into Raymond's bedroom and tries to seduce him, while Martha watches in secret. Raymond rejects Myrtle's advances, but Myrtle reveals Raymond's fabrication about the toupee to Martha, who becomes furious. When her conversation with Myrtle turns hostile, Myrtle tells Martha that she is now married to Raymond and she intends to make a go of it. She plans on taking Raymond back to her wealthy family in Little Rock, where she will introduce him to her family, sending Martha back to Mobile on her own. In response, Martha gives Myrtle a handful of pills that make her violently ill. The next morning Raymond, knowing Myrtle is gravely ill, puts her on a bus for Little Rock, promising to drive her car and belongings there and meet her. But after he leaves her on the bus, she dies and her body is discovered by the bus driver.

Raymond next arranges a meeting with a younger woman named Evelyn (Barbara Cason) who has a large home near a lake. Martha and Raymond bicker the whole time they are at Evelyn's; Martha even goes so far as to suggest that Evelyn pair her off in a bedroom with Raymond, which strikes Evelyn as strange since she has been told Martha and Raymond are brother and sister. Finally, when Martha spots Raymond making out on a blanket with Evelyn, she hurls herself into the lake and tries to drown herself. Raymond pulls her out, kissing and comforting her, while Evelyn looks on, confused and disturbed.

Aborting their con on Evelyn, Raymond decides it is time to give Martha what she has always wanted: a suburban home. They find a home in Valley Stream, NY, but Raymond quickly becomes frustrated as their funds dwindle.

Raymond decides it is time to go back to work, and they set up a meeting with an older woman named Janet Fay (Mary Jane Higby). Janet is well into her 70s and is sitting on a bank account worth over ten thousand dollars, a fact that she happily discloses to Raymond. They move in quickly on Janet, with Raymond proposing to her and Janet moving out of her apartment and going back to Valley Stream with Martha and Raymond. Janet, however, is irritating to Martha from the very beginning, arguing with Martha about petty finances and making vaguely critical remarks about Martha's weight.

They get Janet back to Valley Stream under the pretense of Janet marrying Raymond (who has told her his name is "Charles Martin") and then using her ten thousand dollars to open a hat shop. They get Janet to write them checks that they will presumably take to the bank and cash, absconding with the money.

But just after she signs the checks, their deception begins to unravel. Martha and Raymond leave Janet alone so they can go to the basement and make love. When they all go to bed that night, Janet becomes suspicious and cannot sleep; she wonders why Martha and "Charles" took her away from Albany without even allowing her to call her daughter and son-in-law. She questions Martha about how well-hidden the checks are. Martha becomes short with Janet and wants to give her a sleeping pill, but Janet is neurotically afraid of pills and won't cooperate. Their argument spirals out of control until Janet becomes determined to use the telephone to call her family. Martha, of course, becomes hysterically angry over it and slaps Janet, raging at Raymond to "give her back her checks and put her on a train back to Albany." Janet goes to her belongings and finds her jewelry missing. Janet finally understands that she is in great danger and begs Raymond and Martha to let her call her daughter. Finally Martha and Raymond realize that they must kill Janet to keep her from talking. Martha hands Raymond a hammer, and Raymond tells her "You do it. If you love me, you'll do it." Immediately Martha strikes Janet in the head with the hammer. As she lays bleeding, Martha and Raymond tie a tourniquet around her neck and choke her to death. Martha reacts with calculated precision, barking at Raymond "Get her off the rug!", while Raymond seems terrified at what they are doing. With Janet now dead, Martha and Raymond make love, with Raymond stripping nude in front of Janet's body before going into the bedroom with Martha. The next day, Raymond and Martha dispose of Janet's body by putting it inside her traveling trunk and burying it under the floor of their basement. They send letters to Janet's family announcing that Janet has married and gone to Florida with her new husband.

Raymond and Martha's next victim is Delphine Downing (Kip McArdle), a widowed woman living alone with her young daughter, Rainelle (Mary Breen), who is around four years old. Martha and Raymond are living with Delphine, and Raymond promises Martha in a private moment that Delphine will be their last victim; he feels she has enough assets to allow Raymond and Martha to finally marry after they swindle her. Martha, however, is frustrated because she and Raymond no longer have much of a sex life because of their living conditions with Delphine. Raymond, as usual, swears he has no attraction to Delphine and that he hasn't made love to her.

However, when Raymond takes Rainelle out for the day, Delphine is alone with Martha and confides in her: Delphine is pregnant with Raymond's baby. She tells Martha they've been making love every time Martha left the house, and that Raymond forbid Delphine to tell Martha they were physically intimate. Delphine thinks it is because Martha has puritanical values, but she wants Martha's help in breaking the news of her pregnancy to Raymond. She also wants Martha to suggest that Raymond marry Delphine on Valentine's Day.

Martha is, of course, furious that Raymond has lied to her and has been making love to Delphine. She tells Delphine that Raymond will never marry her now, and that the only way to handle the situation is to abort the baby. To do this, Martha gives Delphine a handful of pills, but Delphine refuses to take them. Raymond comes back with Rainelle as Martha struggles with Delphine, and he walks into the situation unsure of what is going on. Martha tells Ray that Delphine has "found out everything" and was going to call the police. Delphine now realizes that she is in danger and begs Raymond to help her, but Raymond tells Martha to get Delphine's gun, and he shoots Delphine in the head. Martha debates what they should do with Rainelle; Raymond wants to abandon her at a children's home, but Martha feels Rainelle is too old and will remember details about them. She goes to the basement and fills a washtub with water, then takes Rainelle downstairs and drowns her in it, while Raymond listens upstairs, horrified.

Martha has resigned herself to the fact that Raymond will never be truthful to her. Raymond promises that he can set up another meeting with another victim in New Orleans, and he swears to Martha he will not touch her or make love to her. "I didn't touch Delphine, did I?" he rationalizes. Martha kisses him passionately and goes upstairs, where she phones the police and summons them to the house pretending to be a neighbor. When the police arrive, she goes downstairs to let them in, kissing Raymond one more time.

In the film's denouement, Martha is in prison, where a matron meets her to take her to her first day on trial for the crimes she has committed with Raymond. This will be the first time she has seen Raymond since her incarceration, and she is excited. The matron gives Martha a letter from Raymond, which Martha reads alone as she sits on a bench. In the letter, Raymond professes his love for Martha again; he tells her she is the only woman he will ever love, and the only woman he has ever loved. He looks forward to the possibility that one day when they are old, they may have a short time to spend together. The film ends with a title card that informs the viewers that Martha and Raymond were executed for their crimes while incarcerated in Sing Sing prison.