Prologue: The film opens with an awards ceremony honoring Eve Harrington (Anne Baxtor) and narrated in voice-over by Addison Dewitt (George Sanders), a theatre critic whose pompous tones sent the stage for a campy romp through the cast of characters. Reaching Karen Richards (Celeste Holm) the microphone passes to her… and the rest of the movie is told as her flashback and memories. Her voice alone will be the narration for the rest of the film, until the epilogue (which will come back to this awards ceremony).
Karen remembers back to less than a year ago when she met Eve Harrington outside of a theatre in which Margo Channing (Bette Davis) was performing. Karen is married to the writer of the play, Lloyd Richards (Hugh Marlowe) and so has the connections to bring Eve backstage which she does. There Eve is introduced to much of the rest of the cast, Margo, her boyfriend, Bill Sampson (Gary Merrill), Lloyd, and Margo’s Maid/Dresser/Confidante, Birdie Coonan (Thelma Ritter).
Act I: Like the opening of a play, this scene serves as an introduction to the characters, and they all get a chance to soliloquy a bit on who they are and what are their motives. We learn that Bill is about to go to Hollywood to help with the production of a movie. Eve is opposed to film since it’s not “real theatre” but Bill goes on a bit of a rant that theatre is everything from Radio to Vaudeville and Movies – possibly even including television. Each person can take his or her pick. Margo and Bill are best friends with Karen and Lloyd. Birdie keeps an eye on everyone. Margo takes a shower and Eve takes her costume out to have it hung up. Margo goes to stop her and finds Eve holding the costume up and bowing in front of a mirror as if to an audience.
As Margo gets ready to take Bill to the airport for his flight out west, she invites Eve along for a coffee after. At the airport, Eve takes care of everything to give Bill and Margo a chance to say goodbye. That coffee after the airport turns into Eve coming to live with Margo as her assistant.
Act II: The scene shifts to some unspecified time later with the voiceover commenting on how orderly Eve has made things for Margo. There is a scene where a scheduled phone call comes in at 3AM to Margo. (This was a thing you used to be able to do.) Margo wakes to discover she has placed a call to Bill in Hollywood. After some confusion, she remembers it’s Bill’s birthday. She discovers from the phone call that Eve has made arrangements for a birthday party for Bill when he comes back. Then comes a breakfast meeting where Birdie shares with Margo her concern that Eve is “studying her” like an actress learning a part. Margo thinks this is a compliment, Eve wants to be like her, what’s wrong with that? Enter: Eve. She is dressed in one of Margo’s older dresses. She present’s Margo’s day and then as Eve is leaving Margo asks if she (Eve) scheduled a call for midnight in California? Eve feigns surprise that she forgot to say anything about it and, in passing, notes that she sent a telegram herself. Birdie looks at Margo with a “see? I told you” sort of look.
Act III: The Birthday Party is dramatic. Margo thinks Bill is having an affair with Eve. She accuses him of falling for a younger woman. Bill brushes her concern aside. Karen and Lloyd arrive and wonder what is (or is about to) happen. Davis says, infamously, “Fashion your seatbelts it’s going to be a bumpy night.” Addison Dewitt arrives at the party with Miss Caswell, a younger actress in tow, played by Marilyn Monroe. Her attendance at this evening is try to flirt her way into the theatre. By the end of the night, Margo is quite drunk and the party a shambles. The rest of the cast is seated on the stairs watching folks come and go. Here we learn that Eve’s life-long desire and love is to be in the theatre. Oh why, if there’s nothing else, there’s applause; I’ve listened backstage to people applaud. It’s like… like waves of love coming over the footlights and wrapping you up. Imagine, to know every night different hundreds of people love you; they smile, their eyes shine, you please them, they want you, you belong. Just that alone is worth anything. Karen has the idea that Eve should be Margo’s understudy in the new play that Lloyd is writing: Margo has never missed a performance in her entire life. It could only be a good experience for Eve. Margo is asked if she will read lines with Miss Caswell at an audition if it’s not beneath her.
Act IV: Margo is very late for the audition and discovers that Eve has read her part for her. Miss Caswell is rather a wash, but Addison lets Margo know that Eve’s performance was “full of fire and music” and lets Margo know that Eve is her understudy. This arouses all of Margo’s jealousy around Bill and Eve. Entering the theatre, she has a fight with Bill and with Lloyd about Eve taking over. Lloyd leaves angry. Bill tries – and fails – to convince Margo that he loves her and this is all in her head. They break up. When he’s leaving, Margo asks if he’s going to find Eve. Lloyd arrives home and Karen becomes involved in the fight in the third person, though her husband. She hatches a plot. Everyone is supposed to go up to the country for the weekend. Eve places a few extra phone calls.
Act V: Bill never goes to the country house. Margo, Karen, and Lloyd have an awkward time and they are driving back to the train station to send Margo to the evening’s performance. Lloyd and Margo make up. Then the car runs out of gas and Lloyd leaves to find a farm house with gas or something. Margo and Karen make up over a conversation and a smoke, with Margo admitting that she is a successful actress with nothing to fear, but she’s been bad to Eve. Don’t fumble for excuses, not here and now with my hair down. At best, let’s say I’ve been oversensitive to her…to the fact that she’s so young, so feminine and so helpless, too so many things I want to be for Bill. Funny business, a woman’s career. The things you drop on your way up the ladder so you can move faster. You forget you’ll need them again when you get back to being a woman. There’s one career all females have in common – whether we like it or not: being a woman. Sooner or later, we’ve got to work at it, no matter how many other careers we’ve had or wanted. And, in the last analysis, nothing is any good unless you can look up just before dinner or turn around in bed – and there he is. Without that, you’re not a woman. You’re something with a French provincial office or a – a book full of clippings, but you’re not a woman. Slow curtain. The End.
Act VI: Getting back to the city, we discover that Eve, as the understudy, has filled in for Margo. This was planned by Karen who had drained the gas from the car! Eve had called all the press in to watch her performance which was a huge success. The papers the next day – especially Addison’s- are filled with snarky comments about a woman who is 40 (Margo) acting in the role of a twenty-year-old character. This triggers Margo’s insecurity on top of the fight with Bill. As she is having a breakdown in her apartment, Bill bursts in. They embrace and are reconciled. At dinner a few days later, everyone returned to status quo ante, Margo and Bill share with Karen and Richard the good news that they are to be married and want their best friends to be their Best Man and Maid of Honor. There is much rejoicing. Eve arrives at the same restaurant with Addison. There are some sour grapes. Then Eve asks for a private conversation with Karen. In the Ladies’ Room, Eve blackmails Karen by threatening to tell about the gas-understudy incident and, in return for not saying a word, wants to be the Lead in Lloyd’s new play. Karen agrees. However, returning to the table, she hears Margo ask Lloyd to excuse her from the play since she’s going to be busy being a wife. Karen Laughs.
Act VII: This takes place entirely in New Haven, Connecticut, at the theatre where Eve is staring in Lloyd’s new play and in her hotel room. Addison reveals that he knows all about Eve. I’ll skip the serious spoilers here, but he confronts her with lie after lie, and with proof of how she manipulated Karen and Margo. He let’s her know that he’s known this all along and still supported her and now he will see her rise to the heights of stardom if she will take him with her. Otherwise, he will print the truth far and wide, and she will be destroyed. She concedes defeat. The play is a success. Eve becomes madly famous. And the movie ends at the award ceremony where it began.
Epilogue: After the award ceremony Eve goes home. In her splendid new apartment there she mixes a drink and discovers a young woman sleeping on her chair. The woman had snuck in while she was gone and was going all fan girl on being in Eve’s apartment. There are Eve Harrington Clubs “in all the girls schools” now and this is the president of one such club named, named Phoebe. Eve recognizes one of her own kind and sets her to work, helping her to pack and putting things away. A knock at the door which is answered by Phoebe. Turns out Eve left her award in the car and Addison has brought it back. Phoebe takes the award and enters Eve’s bedroom. Taking up Eve’s fancy cape, Phoebe looks in a mirror pretending to be an actress receiving an award.
As the music swells to a climax, with a tune reminiscent of The Crown Imperial, the mirror become becomes a many-paneled room of mirrors, surrounding Phoebe and revealing hundreds of images of the same girl, in the same cape, with the same award, bowing over and over again. The end.