The film opens with a voice-over narration from Anne Welles (Barbara Parkins
). She reveals how she started a journey toward success by leaving her small New England town for New York City. When she gets to the city, she takes a work assignment with a talent agency, and immediately she starts to discover the harsh realities of show business. The agency sends her to a local theater to deliver contracts to renowned performer Helen Lawson (Susan Hayward
). Helen's agent warns Anne not to let her guard down around Helen, and Helen's abrasiveness shocks Anne, who was expecting Helen to be true to her glamorous image. Instead, Helen is tough talking, uses vulgar language, and Anne's idle chatter with Helen sparks a terrible reaction and she sees first hand the evil and selfish woman that Helen really is. When Anne comments that a young woman singing down the hall is very good, Helen agrees, and immediately decides to have the girl fired from the show because the egotistical Helen fears being upstaged. Helen sends Anne back to the office with the contracts in shreds, threatening to leave the agency if Anne's boss doesn't get rid of the competition.
The young girl that Helen sees as her rival is Neely O'Hara (Patty Duke
), a talented up-and-coming singer. She is distraught when she finds out that her musical number has been cut from the show. Since all that remains for her is just a few lines of dialogue, she decides to leave the show all together. Also part of the show is a lovely showgirl named Jennifer North (Sharon Tate
), who sympathizes with Neely when she's cut from the show.
When Anne returns to the office to give the news about Helen (whom Anne now refers to as an "evil queen bitch"), she instead finds the agency's younger partner, Lyon Burke (Paul Burke
). Burke and Anne are immediately attracted to one another, and when Anne tells Lyon that she wants to leave the agency after her frightening brush with the mean-spirited Helen, Lyon persuades her to stay. Pulling some strings for Anne's new friend, Lyon sets up Neely to appear on a popular telethon, where she is immediately noticed. Neely and her boyfriend, Mel (Martin Milner
), live in a humble apartment in New York, but after her career takes off they are married. Neely's popularity skyrockets and her demanding schedule for concerts and singing gigs leads her to start taking pills. Neely first takes caffeine pills to wake her up in the morning as well as amphetamines keep her going during the day, then takes downers to help get to sleep at night.
Anne and Lyon embark on a tenuous affair. Anne seems shy about spending the night with Lyon, and she brings up the idea of marriage. Lyon firmly declares himself a bachelor, however, and does not approve of the idea of marriage. When Anne's mother dies, she goes back to her home town to mourn, and Lyon joins her there later. They have a moment of reckoning; Anne makes it clear that she feels cheap for being sexually involved with Lyon knowing that he will never marry her. Lyon leaves a farewell letter for Anne the next day, telling her that he can no longer see her. Simultaneously, Anne gets a sudden opportunity to model for a cosmetics company, and she becomes a nationally known figure. Anne's face now appears on TV commercials, billboards, newspaper and magazine advertisements.
Meanwhile, Jennifer begins an affair with Tony Polar (Tony Scotti
), a lounge singer whose career is also mounting. Tony's sister, Miriam (Lee Grant
), manages every aspect of Tony's life, and reacts to the relationship with icy disapproval. A little later, Jennifer and Tony get married secretly, and Miriam is despondent.
Elsewhere, Neely's fame eventually proves to be too much for her. Her Broadway stardom leads to a career in the movies as she relocates to Hollywood, but her addiction to pills (which she refers to as 'dolls') sabotages her life. She loses Mel when he becomes weary of her vicious and unpredictable behavior, as well as her rumored affair with a Hollywood designer named Ted Casablanca (Alexander Davion
). When Mel leaves Neely after filing for divorce, she becomes associated with Ted and ultimately marries him.
Jennifer's married life with Tony seems happy enough, although Miriam lives with them and obviously imposes on their marriage. After moving to Los Angeles, Jennifer and Tony settle in a house while Jennifer's modeling career flourishes, Tony's career has peaked, having made the crossover into motion pictures without the same drug-induced success as Neely. One evening, Tony begins to lose control of his motor functions, and Miriam finally reveals to Jennifer why she never wanted Tony to marry: Tony suffers from a rare motor-reutron disease called Hunington's Disease, (similar to A.L.S.) that will ultimately render him senseless and eventually kill him. The disease is genetic and was passed down to Tony from his father who died from the disease several years ago. Jennifer is mortified, because she has just discovered she is pregnant.
Some months later, Anne and Lyon rekindle their affair after her modeling success, with Anne leaving behind another beau to reunite with Lyon and relocate to Los Angeles (as well as keep in close touch with both Neely and Jennifer), but she still seethes inside over the knowledge that Lyon isn't interested in marrying her. Neely shows up at her house one night while Lyon is on a business trip, and she tells Anne that Jennifer called her wanting to know where she could get an abortion. Neely also offers Anne some of her pills to help her get through her lonely period with Lyon gone, but Anne bitterly refuses. Neely's conversation with Anne sparks something in her; when she confides in Anne that her marriage with Ted is on the rocks, Anne encourages her to try and renew the spark in their relationship. Neely returns home to her home in the Hollywood Hills only to find Ted frolicking in their backyard swimming pool with another woman. They have a bitter fight and Ted walks out on her.
Sinking further into alcohol and pills, Neely is thrown off of the current film project she is working on due to her drunkeness and verbal fights with the crew. When Lyon attempts to get her to a sanitarium to dry out, she sneaks off to San Francisco and spends a few days wandering while drunk and stoned. After she is robbed by a strange man, she is finally picked up and taken to a clinic in L.A. by Lyon and Anne. While there, she goes through some horrible withdrawal symptoms and has some bizarre run-ins with the other residents in the sanitarium. However, she is inspired when she discovers that Jennifer's husband, Tony, is also in the same hospital, now almost completely debilitated. Neely and Tony sing a song together in the hospital recreation room before he lapses back into senselessness. This incident prompts Neely to struggle back to sobriety.
Jennifer, meanwhile, is struggling with her own demons. She also begins taking pills and booze to help her cope with Tony's absence as well as an escape for her loneliness. Consistently told by her selfish and manipulative mother that she has no real talent and is only known for her beautiful body, Jennifer turns to making "art" films with a French director to make money. She feels her integrity is compromised by doing this, as she is still loyal to Tony and did most of her sexually provocative work before she was married to him. The high cost of Tony's hospital and sanitarium bills forces Jennifer to do the work, and the situation is made worse when she finds herself locked into an oppressive contract with the director which makes Jennifer slide into taking more pills and booze to suppress her emotions. She continues making softcore and hardcore "art films" while completely numb of feelings.
Emerging from the sanitarium with what seems to be a fresh outlook, Neely makes a cryptic statement to Anne about "stealing her man". When Lyon takes Neely to New York to prepare for her comeback to the stage, the two of them share a hotel room, and it becomes clear to Anne that they are involved on a physical level. This is made more hurtful when Anne sees her name in the gossip column, the columnist commenting about how she is a "big loser" due to Neely and Lyon flaunting their affair all over New York. Anne finally succumbs to the lure of the "dolls", at first taking Neely's old pills and then getting a prescription of her own.
In New York City, Lyon gives Neely strict orders to stay out of sight until the debut of her new Broadway show, but when he goes to a party in honor of Helen Lawson's new show, Neely makes an uninvited appearance. The photographers and reporters present give her a huge welcome, much to Helen's chagrin, and she slips off to the ladies room to avoid the ruckus. Neely, however, goes after her, and the two of them have a cat-fight in the ladies lounge. When the fight turns really ugly, Neely winds up tearing off Helen's wig, revealing her unflattering grey hair color underneath. Throwing Helen's wig in the toilet, Neely renders her unwilling to step back out into the party. Helen momentarily considers slipping out the back, until she resolves to face the party again with her hair wrapped in a colorful scarf.
Back in Los Angeles, Jennifer's story comes to a sudden and sad close when she is diagnosed with breast cancer. She learns that she must have a mastectomy and checks herself into a hospital to have it done. But this is the final blow for her, as she feels that now she won't be able to support herself without her lovely body to rely on. After coming home from the hospital and following a friendly visit by Annie, Jennifer commits suicide by taking an overdose on pills. Her body is discovered the next day.
Alone one day and devastated over Jennifer's death as well as the loss of Lyon to Neely, the drunk and stoned Anne wonders down the beach beside her house and after passing out in the surf, she returns to her house and smashes several furniture to pieces. She then decides to leave it all behind and a few days later, she returns to her snowy New England hometown where she is welcomed back by her aunt.
In New York, Neely blows her big chance for her Broadway comeback when she gets into an argument with Lyon beforehand. She disregards him by saying "Who needs you? You're just an agent!" Lyon abandons her, no longer able to tolerate her egoistical behavior, and in response, Neely turns to a secret stash of pills. When it comes time for her stage entrance, Neely is completely disoriented and unable to perform, giving her understudy the chance to perform on opening night. Neely spends the night getting drunk in a nearby tavern, ultimately finding herself alone and disoriented in a deserted downtown alley.
The next morning, Helen Lawson has a candid conversation with Lyon. She predicts that Neely will come back yet again from her latest blunder, simply because she has true talent, but that ultimately she'll destroy herself. She also warns Lyon that he should stop being so careless with his love life and settle down with Anne, before it's too late.
Lyon seems to take this advice to heart and he travels upstate to Anne's snowy hometown where he proposes marriage to Anne, but it is indeed too late for them. Anne admits that she has waited so long for Lyon to propose that she now feels nothing when the offer's been made. Having emerged from her brief drug episode with a fresh outlook, Anne seems to be the only one among the three ladies who has learned from her experience. After pouring all her liquor bottles and pills down a sink, she walks off alone into the snowy landscape of her home town and ponders her next move alone and without the need for drugs or alcohol.