A female superstar struggles through the trials and tribulations of being a Bollywood actress.
After his incredible run of women-centric films from Chandni Bar, Page 3, Satta and Corporate to the blockbuster Fashion, Madhur Bhandarkar now turns his lens inwards and presents his most ambitious work yet - Heroine. The film is based on the life and times of a superstar heroine from the dream factory we call 'Bollywood'. The film is a daring, shocking, glamorous, scandalous behind the scenes account of the reality behind the world of glitz and glamour that our film stars inhabit. For a country obsessed with films and film stars, Heroine will take audiences on a voyeuristic journey to see what really goes on behind the closed doors of make up rooms and vanity vans. It will give them a chance to go beyond the gorgeous smiles and politically correct quotes, to see what really happens in the lives of India's sweethearts. The bitching and the politics, the secrets and the lies, the incredible highs of fame and the lonely depths of failure.—Anonymous
Mahi Arora (Kareena Kapoor), a renowned heroine is thrown out of a car at night. She hails a taxi to a police station with the intention of lodging a complaint. Before she can do so, her secretary Rashid Bhai (Govind Namdeo) takes her away from the station.A journalist Tamanna (Dilnaz Irani) reports on the life of Mahi Arora, a renowned film actress, describing her as unstable and problematic, but damaged and lonely due to childhood trauma, and bipolar disorder.
In flashback for a while, we see the circumstances and Mahi's relationship with a well-known actor Aryan (Arjun Rampal). Aryan is in the divorce proceedings with his wife and dating Mahi. Mahi and Aryan are doing a movie together, but the director is not happy with Mahi's work in the movie. Mahi believes that Aryan is not serious about her or their relationship. Mahi wants to go to a vacation to Bahamas with Aryan, but he is non-committal.
Mahi is completely in love with Aryan, and during one of their intimate moments, takes a video of them just for fun. Aryan is split between his current wife Isha (Shilpi Sharma) and son Akshit, his career, and over-jealous Mahi. Isha is holding off on signing the divorce papers as she wants one more property in her name as part of the settlement. Aryan is disgusted as he has already given her 3 properties and Rs 10 Crores in cash.
Mahi's rivals include Rhea (Mugdha Godse), Gayatri, Promita (Shahana Goswami), Shaheen (Pooja Chopra) and others. Mahi's mother (Lillete Dubey) lives in Delhi and spends time seducing politicians, which Mahi does not like.Mahi knows that Rhea is using underhanded tactics to steal away endorsements from her, and plants negative stories about Mahi in the press through Tamanna by offering free vacations for her entire family.
When Mahi comes to know about an intimate scene Aryan is shooting for a movie with Rhea, she barges on to the set and creates a ruckus, which upsets Aryan. Aryan asks Mahi not to come to a common friend's anniversary party as Isha is going to be there. Mahi ignores Aryan and arrives for the party, shocking everyone.Later Mahi is teased by Isha in the party, and she insults her back. While driven back from the party with Aryan, Mahi raises the topic, which results in her being thrown out of the car.
Mahi then goes into depression, putting her career in jeopardy. The entire industry supports Aryan as he is the superstar & the offers dry up for Mahi.One of her friends suggests Mahi to stop playing the victim and to get back again with a bang. Heeding her advice, Mahi decides to rejuvenate her career. She employs a PRO, Pallavi (Divya Dutta) who reinvents Mahi's image and puts her back on the front page of all newspapers and magazines.
She then finds solace in the arms of an upcoming cricketer, Angad Paul (Randeep Hooda). Angad is the Vice Captain of the India national cricket team.Pallavi advises Mahi to kindle an affair with Angad to gain even more publicity. Mahi is reluctant to use Angad in this way, but Pallavi overrides her feelings. Mahi ensues a fake love affair that begins to blossom for Angad, and this puts Mahi back into the spotlight.
Mahi gets more confident & assertive. She uses her connections effectively to subvert the careers of her rivals & generate opportunities for herself. She is egged in this endeavor by the over ambitious Pallavi, who supports & encourages her every decision. Mahi even uses Angad's connection with an actor's wife to get him to choose Mahi as the co-star for his next film, edging out her fierce rivals.
The lead actor of the film, Abbas Khan (Sanjay Suri), a married playboy, attempts to initiate an affair with her. She rejects him, which causes him to seek revenge. He demands that the director re-edit the movie so that the story becomes about him and an item girl Gayatri (Pallavi Sharda). Mahi is dissatisfied despite the film being a success, and in a desperate attempt to prove her acting skills, works in a low-budget art film for months.
However, when Angad proposes to Mahi, she blatantly refuses as she feels this is the time to concentrate on their respective careers. This causes Mahi and Angad's relationship to dissolve too.Mahi bets on an art film with an eccentric director. The move pays off in terms of Mahi's acting skills, but backfires when the production house pushes the director to make the film more commercial & he shuts it down. Mahi tries adopting a baby, but her application is refused when she is found to be alcoholic & to be receiving psychiatric treatment. Mahi is shattered & fires Pallavi for trying to make publicity out of her personal misery.
As fate would have it, Mahi meets Aryan at her friend's wedding. Aryan seems to be apologetic to Mahi for what he had done to her. They decide to rekindle their affair. Mahi is happy that Aryan is back in her life. Also, he wants her to do a film with him.
However, the director of the film is reluctant to cast Mahi in the role of the lead heroine as she has lost her appeal. At a poorly-attended press conference for an upcoming film, Mahi is mocked by journalists who inform her that the director has cast another actress opposite Aryan. Mahi becomes insane about losing the role to another heroine. She asks Pallavi to leak the sex tape of her and Aryan on the news so that she would get back on the spotlight.
As a result of this controversy, Mahi's upcoming film becomes an instant hit. However, when Rashid Bhai quits his job and a veteran actress in the industry, Shagufta Reza (Helen) whom Mahi admires dearly, dies, Mahi decides to quit acting as well. Shagufta always used to counsel Mahi to maintain her poise & calm & not to get carried away by the glamour industry & to prioritize her personal life over the glitz of Bollywood.
In the concluding scenes, Mahi is shown walking alone in a foreign country and on being asked if she is Mahi Arora, she replies "no". It is implied that Mahi moved on her life.