From the bottom of a murky swimming pool we see a fully clothed body floating above us. Over this scene the voice of Joe Gillis becomes established…
"I guess it was five a.m., a homicide had been reported from one of those crazy mansions up on Sunset. Tomorrow every front page is going to leads with this story; you see an old time movie star is involved… Maybe the biggest star of all."
The scene changes and we are transported back 6 months to the busy Paramount Studios. As Joe wanders through the crowds he greets several acquaintances; "Lets have lunch… gotta run". Soon, however, he bumps into two men in hats and bad suits: Financemen. "We want the keys to your car. You're way behind with your payments". Desperate to keep his car, Joe slips away into the crowd where he meets his agent. "You've got to find me a job!". His agent cannot help however; he is too busy with his new prodigy. Disappointed, Joe moves on to the offices of Paramount; he has an appointment with Sheldrake, a producer, to talk about a screenplay Joe has submitted. Sheldrake summons someone to "bring in whatever we have" on Joe's script. Betty Schaefer, a young staff member brings in the synopsis she has prepared, but she makes it clear she thinks Joe's screenplay is pretty awful: "It's just a re-hash of something that wasn't very good in the first place". Suddenly she notices Joe in the room and is obviously embarrassed. Joe is annoyed and will not listen to her when she says insists really liked some of his other work; particularly a short story called 'Blind Windows'. Joe is still stubborn and insists that her idea to turn it into a movie is not worth the trouble "Sheldrake won't buy this story – he likes trash with neon lights". Suddenly the financemen reappear and Joe agrees to discuss the idea further if Betty will distract them while he escapes. They are only put off for a minute, however, and soon they catch up with Joe and a car chase ensues.
Turning onto Sunset Boulevard, Joe sees an empty garage and pulls into it whilst the financemen cruise on unaware. He is taken aback by the size of the garage and the huge luxurious car within. From the veranda of the great house a voice comes; "You there! Why are you so late?"
A solemn figure approaches Joe and leads him into the house, despite his objections. This is Max, the butler. He believes Joe to be the funeral director who has come to arrange a ceremony for their recently deceased chimp. Joe is left alone in the great hall of the house where, through the gloom, he makes out a veiled figure hunched over the body of the dead ape. She is singing a farewell lullaby to it: "I'll see you again when I surrender…". It soon becomes apparent that Joe has no right to be there, but as he turns to walk away, Joe calls back "Aren't you Norma Desmond? You used to be in pictures. You used to be big!" Her curt reply comes: "I am big. It's the pictures that got small!". She lectures Joe on how the film industry has been ruined by the advent of 'talkies': "They threw away the gold of silence when all they needed was this face of mine". Joe insists "Don't blame me; I'm just a writer!", but there is no stopping Norma. "With one look I can break your heart" she goes on. She fully believes she can still be queen of the film industry. As Joe turns to leave once more, Norma calls him back: "Did you say you were a writer?". She hands Joe a think bundle of manuscripts. "I wrote this..." she proclaims, "It's a very important picture". She insists that Joe reads it, despite his obvious objections: "It's about Salome – the woman who was all women". After skimming the script, Joe has a few objections: "Could be it's a little long… Shouldn't there be some dialogue…? It could use a few cuts." Norma decides Joe is the person to perfect her 'masterpiece' and that he should stay the night and start his work early tomorrow. Max leads him to the sparse guest room and there describes Norma's once glorious career "If you said 'Hollywood', hers was the face you'd think of… Today, she's half forgotten, but it's the pictures that got small; she is the greatest star of all…"
The next day, Joe arrives at Schwabb's Drugstore where he agreed to meet Betty. At the bar, he meets his friend Artie Green and learns that Betty is his bride-to-be. Joe and Betty discuss the possibility of filming Blind Windows, but Joe will not be persuaded. He tells her to write the script herself and call him if she has any problems. They bid each other goodnight and Joe drives back to the Norma's mansion. He meets Max on the patio who reveals he is "greatly worried about Madame". He knows she has no hope of being a star again; her fans have deserted her leaving him to write fan mail to her so that she doesn't realise her once loyal followers have left her for the new stars of Hollywood. Joe, he says, must not leave the house to avoid upsetting Norma. In the days that follow, Joe "hack(s) (his) was through the script" which turns out to be a bigger task than he had thought. The only entertainment available is Norma's old silent movies, which they watch together as she relives her past triumphs. Joe is marooned in the house, and even when he completes the script he is unable to leave; his car has been towed away and he has not been paid for his work.
One morning, Norma marches into the room and announces "Today's the day!". She instructs Max to take the script to Paramount and give it to Cecil B. DeMille "in person". Joe thanks Norma for her faith in his abilities and makes to leave; "the script is finished". Norma, however, has other plans. She passionately proclaims "You'll stay on with full salary, of course… I need your support!" and pleads with Joe to stay. He agrees. December 21st comes and Norma arranges a special treat for Joe; tailors from "the best men's shop in town… I had them close it down for the day". The oily manager attempts to kit out the reluctant Joe in the finest merchandise he has; "second rate clothes are for second raters!" Joe is left with a huge pile of boxes and packages ready for Norma's New Years Eve celebration which she insists he attends.
The party night arrives and Max has "pulled the stops out". The house looks fabulous, the drinks are ready and on the staircase a string quartet is discreetly playing. Joe enters the room, dressed in his new clothes; tails and black tie. The guests, however, are not visible. Norma struts in wearing an amazing creation, and gives Joe a present; a gold cigarette case engraved with "mad about the boy". As the band start a tango, they move to the dance floor and the atmosphere is electric. They hold each other closely as they twirl round the tiles and Norma whispers in Joe's ear of her plans for their next year together "if you're with me, next year will be the perfect year". Joe seems contented with the notion for a few minutes, and they move to the sofa as the music ends. Joe enquires when the other guests are due to arrive and Norma answers "there are no other guests! Just you and me. I'm in love with you, surely you know that." Joe objects: "What right do you have to take me for granted… I'm the wrong guy for you". Norma: "What you are trying to say is "You don't want me to love you. Say it! Say it!" Norma slaps Joe and he storms out, taking a taxi to Artie's apartment where quite a crowd has gathered.
The young hopefuls are sharing their New Year's resolutions to succeed in Hollywood: "Hope we're not still saying these thing this time next year!" Betty is still in need of Joe's help in the writing of Blind Windows, but Joe's opinion has not changed. Betty, however, is able to persuade him that her's is a good idea. Joe decides to stay with Artie until he can find somewhere to live and work on the screenplay. He rings Max and asks him to bring over his things. Max has no time for this, however. "I am attending to Madame," he insists, "She found the razor in your room and she cut her wrists." Joe grabs his coat and rushes back to the house on Sunset.
He finds Norma lying on the sofa, her arms bandaged.
"What kind of a silly thing was that to do?" he asks.
Norma is upset: "You must have some girl. Why don't you go to her?
"I never meant to hurt you, Norma. You've been good to me" he insists.
"Why don't you just say thank you and go? GO! GO!"
Joe goes to leave, but then turns and faces Norma: "Happy New Year" he whispers to her.
"Happy New Year, Darling" she replies.
As the curtain falls, he embraces her and they kiss.
Act two begins beside Norma's swimming pool. Joe is lounging in a cane chaise-longue, sipping a cocktail. He addresses us whilst smiling smugly: "Sunset Boulevard; jackpot boulevard. She was sinking fast, I threw a rope. Now I have suits and she has hope. You think I've sold out? Dead right I've sold out!"
Norma rushes onto the terrace: "There's been a call! Joe, Paramount! They love our child. Mr. DeMille is going wild! But it was some fool assistant; if they want me, then Cecil B. himself must call."
He never does call, but after 3 days, Norma decides she is 'ready'. She dresses up "like a pharaoh" and Max drives to Paramount. Joe sends Norma to see Cecil B. on her own; "It's your show." When Norma pulls up outside Stage 18, the director is surprised to say the least. He avoids answering Norma's awkward questions about filming her script, instead rushing her into the film-set before she can persist any further. As she gazes around the crowded area, bustling with excitement and mystery, she is quite overwhelmed. She recalls her life as a star, and consoles herself by saying she will soon be back making a picture: "This time will be bigger! Everything's as if we never said goodbye."
Outside the sound-stage, Joe bumps into Betty. She says that she needs his help to write Blind Windows. Joe makes excuses and says he will call. Meanwhile, Sheldrake approaches Max. He recognises him as Norma's butler, and asks why she hasn't returned his phone calls about hiring her car for use in a movie. Max suddenly realises the implications of this and tells Joe: "It's not Madame the want; it's her car!" Norma says fond goodbyes to Cecil B. and cruises back to Sunset. He recalls her days as the world's brightest star.
Joe and Betty finally get to work on the script. Joe discovers that it's "fun writing with a partner" and they work productively. Norma is hard at work too. In the mansion, she is lying on a couch whilst a swathe of beauticians and dieticians work on her body. She is eager to get back into shape for her 'return' to show business. "Eternal youth is worth a little suffering" they console her.
Joe soon returns from his script-writing session with Betty. Norma suspiciously enquires about his whereabouts "Who is Betty Schaefer?" He tells her "there's nothing to worry about. I haven't done anything."
After a few days of work, the script is finished. Joe and Betty celebrate with a trip to the water cooler. As they walk, Betty tells Joe about her childhood around the Paramount lot: "I was born two blocks from here." Soon, the topic of Artie arises: "He wants me to come out to Tennessee", Says Betty, "But… I'm just not in love with him any more… I.. love.. you." Joe realises he feels the same way: "If I'm a fool, well I'm too much in love to care." They kiss.
Joe arrives back at the mansion late. Max is waiting. He warns Joe to be careful, he does not want Madame upset: "I made her a star, I will never let her be destroyed… I directed all her early pictures. In those days there were three young directors who showed promise… D.W. Griffith, Cecil B. DeMille and…" Joe finishes the sentence for him: "Max Von Mayerling." "Please understand," Max goes on, "She was my wife."
Inside the house, Norma is on the phone: "Hello, is this Gladstone 9281, Miss Schaefer? You do know a Mr. Gillis? He's just a, I can't say it… you ask him, I'd love to hear his answer…" Joe grabs the phone "Why don't you ask me? Come over.. right now." Norma pleads with him, but he is enraged. Outside, a storm is brewing and when Betty comes rushing across the patio from her car she is soaked. She rings the chimes and Joe lets her in. "What' going on, Joe?" she asks. Joe is firm. "It's the oldest story in the book… older woman, very well to do, meets younger man - the standard cue for two mechanical performers. You want me to go back to living on subsistence? You should go back to Artie and marry the fool, and you'll always be welcome to swim in my pool!" Betty rushes out weeping: " I can't look at you any more."
Norma is pleased: " Thank you!" Joe, however, has rushed upstairs and returned with his suitcase. "What are you doing, Joe?", Norma asks, " You're not leaving me?" Joe sharply answers: "Yes I am, Norma, and there's something you ought to know… they'll never shoot that hopeless script of yours. They only wanted your car." Norma is shocked: "That's a lie! What about all my fanmail?" Joe has an answer: "It's Max who writes your letters. Nothing's wrong with being 50 unless you're acting 20!" Norma is enraged. She pulls the revolver from her robe as Joe turns to leave, and shoots: "No-one ever leaves a star!" Joe jerks as the bullet hits him, but keeps on walking, down the steps, out the French doors and as the third shot hits him, he falls into the swimming pool.
As dawn breaks, the lights come up on the hall of the house. It is filled with film crews and reporters. One speaks into the camera "Norma Desmond, famed star of yesteryear is in a state of complete mental shock." Norma emerges at the top of the staircase in a Salome-type costume. She descends the staircase slowly, singing fragmented lines of song. She is obviously distressed and bewildered. Max calls out: "Madame, the cameras have arrived. This is the staircase of the palace and they're waiting for your dance." She does not doubt this, and as the cameras whirr, she gestures and begins an extraordinary slow dance. She fully believes she is being filmed for her movie, but suddenly breaks off: " I can't go on with this scene; I'm too happy. This is my life. It always will be. And now, Mr DeMille, I'm ready for my close-up..."
"This time, I'm staying, I'm staying for good. I'll be back where I was born to be. With one look, I'll be me."