(Note: The stage action is continuous. Follies can be played with or without an intermission, as indicated in the script.)

An old, dusty curtain rises to the sound of soft timpani; the stage of a large, long-unused theatre becomes visible. A tall, pale, ghostly Showgirl, dressed in black and white, starts to move slowly. Another ghostly Showgirl, also dressed in black and white, enters and begins to walk slowly as the Major-Domo rushes onstage, followed by waiters and waitresses carrying trays of glasses and party equipment. The Waiters and Waitresses move offstage as six Chorus Girls, also dressed in black and white, become visible, dancing in slow motion and silently moving their mouths, as if singing. As Waiters and Waitresses bustle around the unseen ghosts, four musicians enter with their instruments and move to a platform on the stage. Sally Durant Plummer, a 49-year-old former showgirl, rushes in, worried that she might be the first to arrive. One of the ghostly showgirls, Young Sally, moves toward her; Sally doesn't see any of the ghosts. A Waitress hands her a silk sash. The other party guests, former showgirls, chorus girls and their husbands and dates, ranging in age from their 50s to their 80s, arrive and move past the ghosts as the music changes into a pastiche of 1920s and 1930s tunes. Ben and Phyllis Stone arrive; Young Phyllis, another of the ghostly chorus girls, moves toward Phyllis. Sally's husband, Buddy Plummer, arrives and begins asking for Sally.

Dimitri Weissman introduces himself to the guests (and the audience) by announcing that, in the years between World War I and World War II, he produced The Weissman Follies in this theatre, which is to be demolished in order to build a parking lot. He welcomes the guests to this gathering, the first and last reunion of The Weissman Follies. He asks Roscoe, an elderly man in top hat and tails, to sing the song that will bring on the former Weissman Girls one last time ("Beautiful Girls"). Each of the ladies, wearing a sash with the date of her Follies year marked in gold, makes a grand entrance down the Follies stairs as Roscoe sings; they parade across the stage. Buddy finds Sally when the song ends; she is worried that he might be upset with her for taking an earlier flight. As they talk, a couple begins to dance. Stella and Max Deems talk to Weissman about their careers as radio performers. Ben and Phyllis talk to Hattie Walker, a tough seventy-year-old former Weissman Girl. Ben gives her an autograph for her grandson. Phyllis has watched Ben and Hattie, and, after Hattie leaves, Phyllis tells Ben how she admires Ben's charm with women. Solange La Fitte, another former Weissman Girl now in her mid-sixties, tells Weissman about her new perfume lines. Sally begins speaking to Weissman, who doesn't seem to remember who she is.

As she begins recalling other faces in the crowd, Phyllis sees Sally. Phyllis calls out to Sally; at the same moment, Young Phyllis and Young Sally race excitedly down the stairs, busily making the final adjustments to their Follies costumes before their entrances. The present-day Sally at first stares blankly at Phyllis. After Phyllis asks her name again, Sally tells Phyllis that she looks so regal that Phyllis can't hug her. As she embraces Sally, their younger selves race back up the stairs. Phyllis and Sally talk about the apartment that they used to share and ask about one another's husbands. Sally asks if Ben is still in Europe with the UN. Phyllis mentions that Ben is at the party, and the two exit as Hattie Walker muses about how she has outlived five husbands. Ben and Buddy sit on some rubble and discuss the past; when Buddy asks about Ben's life with Phyllis, Young Buddy and Young Ben appear. Young Buddy tells Young Ben that he has arranged a date for Ben with Sally's roommate, Phyllis, a nice, though lonely, girl. Back in the present, Buddy and Ben continue their talk; both of them mention that they've stopped playing around with other women. A waitress walks by; Buddy makes a pass at her and follows her offstage.

As Buddy exits, Vincent and Vanessa, an elegant couple in their late fifties, dance into view; they explain that, after their Follies years, they bought an Arthur Murray dancing school franchise. Heidi Schiller, who is now in her eighties, claims that the Viennese waltz being played by the band was written for her by Franz Lehar. Or was it Oscar Straus? We see Ben as he is recognized by Carlotta Campion, a one-time movie star. They talk briefly, and, as Carlotta moves off, Sally approaches, sees Ben and gasps.

As she says his name, Young Sally appears; she is dressed in a street coat and is demanding that Ben look at her and give her an explanation. The past fades as Sally nervously tells Ben not to look at her yet ("Don't Look at Me"). Ben remembers Sally's endearing habits, and the two of them sing about how they've aged. As they go off to get drinks, Carlotta returns to complain about how the men she meets always want to tell her their life stories but never seem interested in hearing hers. Buddy and Phyllis are dancing and fondly recalling the past. Ben and Sally are dancing nearby; Sally is explaining how she always felt inferior to Phyllis. Buddy asks Phyllis if she remembers all of the fun times that the four of them had; when Phyllis remarks that she has tried not to remember, Buddy recalls how he and Ben used to wait each night for the girls to come down from the theatre. Sally and Ben join them as they recall the old days ("Waiting for the Girls Upstairs"). As they continue to reminisce, Young Sally and Young Phyllis come down the stairs to meet Young Ben and Young Buddy. The four young people argue about where to go for the evening before they are joined by their older counterparts, who relive the argument with their younger selves. Ben, Phyllis, Sally and Buddy finish the song, singing about how foolish they were back then.

A photographer takes pictures of Emily and Theodore Whitman and Willy Wheeler as they talk to Weissman, who is trying to impress a much younger Waitress. Suddenly, the Whitmans perform a song from their act ("Rain on the Roof"); when they are finished, Salonge La Fitte appears, singing one of her signature numbers ("Ah, Paris"). Hattie Walker then performs one of her Follies songs ("Broadway Baby"). Hattie, Salonge and the Whitmans all sing their numbers at the same time; the number ends with a blackout, and a ghostly showgirl moves across the stage as Ben and Sally enter.

Ben tells Sally that, even though his life as a diplomat is not as glamorous as she thinks, he feels he has a good, successful life; the important thing is knowing what you want. Ben never thinks of the options that he ignored ("The Road You Didn't Take"). Young Ben and Young Buddy appear. Young Buddy gives Young Ben the keys to his car and asks him if he has enough money for his date. Ben continues singing about how he won't remember the paths that he didn't choose, all the while remembering Young Ben taking Young Phyllis out on a date. When the song ends, Sally tells Ben that she was in love with him when they were younger; they begin to dance. Buddy tells Phyllis that Sally and Ben make a lovely couple. After telling Phyllis more about his life with Sally, Buddy tells Phyllis that Sally is still in love with Ben. Phyllis tells him that she used to suspect the same thing, but thought that time had changed the situation. Young Phyllis and Young Ben appear; she is admiring the engagement ring that he has just given her. She tells Young Ben that she shall try to be a good wife. As the memory fades, Phyllis angrily tells Buddy that life and maturity are all about making bargains. She tells him how the excitement with one of her ex-lovers passed with time, and how, at the end of the affair, she was still Mrs. Stone and had $30,000 worth of silver in her dining room. When Buddy asks what happened to the young, innocent Phyllis, she tells him that she has made her own choices and walks away. Vincent and Vanessa appear and begin to dance one of their old routines, a tango ("Bolero D'Amour"); Young Vincent and Young Vanessa and three other ghostly younger couples join in.

Sally tells Ben about the many moves from city to city that she and Buddy made before they settled in Phoenix, Arizona. Sally tells him that the best part of life is knowing that Buddy will always think that Sally is young and beautiful ("In Buddy's Eyes"). Young Sally, who is upset, rushes by, followed by Young Ben. She tells him that she won't continue seeing him after he has given a ring to Phyllis; Young Ben accepts this news, and he and Young Sally embrace as Sally continues the song. Sally and Ben begin to dance.

Phyllis cuts in and draws Sally to the side. When Phyllis confronts her with Buddy's news that Sally is still in love with Ben, Sally sweetly suggests that Buddy is jealous. The band starts to play a song as Phyllis becomes more confrontational. Stella Deems enters and insists that all of the women join in to sing and dance to the song, an old Follies routine that none of them has performed in years. After some protesting, all of the women, including Phyllis and Sally, join Stella to sing about an unhappy woman who never knew real love ("Who's That Woman?"). As the number continues, they are joined by their younger selves.

When the number ends, Ben and Buddy rush up to congratulate Phyllis and Sally. Weissman announces that the food is ready. The two couples separately reveal how troubled their marriages are. After Sally mentions that Ben is unhappy living with Phyllis, Buddy tells Sally that he's decided to spend more time with her at home. Phyllis suddenly kisses Ben, but she is hurt by his unresponsiveness and she confronts him about the lack of honesty in their relationship. Sally confronts Buddy with her knowledge of Buddy's relationship with Margie, a woman in Dallas. Phyllis expresses unhappiness with their marriage; when she accuses Ben of fooling around with other women, he acknowledges this before angrily walking away. Phyllis seduces one of the waiters. Carlotta Campion sings a number from an old Follies show; it is about a woman who has been around a long time and has survived all of the good and bad things that have happened to her, and, as it progresses, the song seems to become more about Carlotta, rather then merely an old Follies number ("I'm Still Here").

Ben tells Sally that he must have loved Phyllis at one time; their marriage was the only impulsive thing that he ever did. Sally tells him that he has always been afraid to feel things and urges him to close his eyes. Young Sally and Young Ben appear, half-dressed, and gazing at each other. Sally tells Ben that all she thinks about is the time that they were in love; Young Sally tells Young Ben how in love with him she is. Ben tells Sally that he wishes he were 25 years old again. Sally becomes lost in the memory as she and Young Sally tell Ben that they will wait for him to return after the war. Ben opens his arms, and Young Sally rushes to him as he lets himself feel how much he has wished that he and Young Sally were still together ("Too Many Mornings"); Sally joins him in the song, which ends with Sally replacing Young Sally in Ben's arms as Young Sally and Young Ben walk off hand in hand. Sally and Ben kiss, and Ben tells Sally that he wants to make love to her. When Sally asks Ben if they are getting married, Ben snaps back from his memory of the past and awkwardly tells Sally that, whatever they had, it all happened in the past. At the same moment, Young Ben tells Young Sally that there is no need for them to marry and walks away from her. Sally ends up standing next to Young Sally and tells Ben that everything will be fine.

Buddy has been asking himself why he stays with Sally; he contrasts his frustrations with Sally to his happiness when he is with Margie, who asks little of him ("The Right Girl"). He begins rehearsing a speech to end his marriage; Sally joins him and happily announces that she and Ben are going to get married.

Ben, now drunk, propositions Carlotta, with whom he once had a brief affair; she gently refuses as Heidi, joined by Young Heidi, appears to sing one of her old songs about the end of a love affair ("One More Kiss").

Phyllis, who has been off in a corner with a waiter, joins Ben, who tells her that he wants to find real love again. When Ben tells her that he wants her to leave him, Phyllis angrily lists all of the reasons why she would leave him but refuses to say if she will ("Could I Leave You?").

Ben, Phyllis, Sally and Buddy watch the innocence and idealism of their younger selves; the older people confront their younger selves and blame them for making choices that have left them unhappy. As this confrontation climaxes, drums roll, heavenly music is heard, trumpeters in Medieval costume appear and beautiful, young dancers dressed as Dresden Dolls and Cavaliers enter: Phyllis, Ben, Sally and Buddy are now in "Loveland." As numerous Showgirls enter and walk the stage, the chorus describes Loveland as the place where lovers are always young and beautiful, and everyone lives only for love ("Loveland"). Young Ben and Young Phyllis dance on, dressed in bright costumes now, and sing a duet about how he will guarantee her happiness tomorrow ("You're Gonna Love Tomorrow"); Phyllis and Ben follow them offstage. Young Buddy and Young Sally dance on and sing a song about how love will allow them to ignore each other's irritating traits ("Love Will See Us Through"). Young Ben and Young Phyllis join them, and the two couples sing their songs together as Buddy and Sally exit. A show curtain drops at the end of the number.

Buddy, dressed in the bright jacket, baggy pants and derby hat of a Follies clown, steps out from the curtain and sings of his true feelings and fears about love ("The God-Why-Don't-You-Love-Me Blues") as chorus girls dressed as caricatures of Sally and Margie flounce around the stage.

Next, Sally, dressed in the elegant dress of a 1930s film star, sings a torch song about how she does nothing but think about her lover ("Losing My Mind").

At the end of Sally's song, Phyllis enters wearing a short red-fringed dress; she sings about Lucy and Jessie, two unhappy women of completely opposite sensibilities who need to become one person to be happy ("The Story of Lucy and Jessie").

Lastly, Ben enters with chorus boys and girls; he sings of a sophisticated man-about-town who fends off his fears by living gaily ("Live, Laugh, Love"). However, Ben forgets his lyrics, and the song ends with him frantically justifying his choices to the chorus, which continues to sing and dance. The entire company returns to the stage, each reprising his or her own song in an ever-rising cacophony that mirrors the terror gripping Ben. Finally, the noise subsides as the madness dissipates; we are back in the real world.

Ben, Phyllis, Buddy and Sally are alone; we can see that the sun is beginning to rise. Phyllis and Ben gather themselves to go home as Buddy helps an emotionally devastated Sally to her feet. As they leave the theatre, Young Buddy and Young Ben call up to Young Sally and Young Phyllis.