Satine is the beautiful and desirable highlight of the Moulin Rouge, where she works as a dancer, and a prostitute.
She has been a regular feature at the Moulin Rouge nightclub for awhile. Satine is cited to be the "star of the Moulin Rouge". It is assumed she worked her way up from the ranks to become the most coveted, and wanted, dancer and call-girl at the Moulin Rouge. She acts as the star performer, and the audience is introduced to her as the 'Sparkling Diamond' she sings and dances along to Diamonds are a girls best friend. Half-way through her routine, Zidler, her father-figure and confidante, confesses that there is a wealthy Duke in presence that night, and in order for him to invest, Satine will have to 'charm' him. She agrees to meet with him that night, but as a result of trickerey by Toulouse, Satine believes the penniless Christian to be the Duke.
Satine approaches Christian, and comfortable in her sexuality, and in her sexual abilities, propositions him, believing that all he needs to want to invest is one night with her. Christian claims that all he wants to do is read her 'poetry', which she mistakes as code for sex. Slightly enamoured by his demeanour and innocent charm, and delighted by the fact that he is young, and neither looks nor acts like a Duke, she invites him up to her elephant, with the intention of sleeping with him.
As she prepares to finish her performance, and prepare for her night ahead, Satine passes out, and falls to the floor where she is caught by Chocolat. Zidler brushes the incident off, pretending it was all apart of the performance. She passed out due to consumption, what is now known as tuberculosis.
Satine awakes, and does not yet know how serious her illness is. Realizing that she is trapped in the Moulin Rouge, she prepares for her night with the Duke. Here we see her desire to be an actress, and become something more. When Zidler discusses the prospect of the play, with her in the lead, she becomes excited, and she intends to leave the Moulin Rouge with this experience, and go on to become 'a real actress'.
Dressed in balck corset and robe and fully prepared to coax the Duke into investing, Satine meets Christian in her room. They talk, and Satine is put off by Christians seemingly no-fuss attitude towards her seduction, he claims he want to get in over and done with, and Satine attempts to oblige.
She then becomes a 'smoldering temptress'. She wants to get Christian 'in the mood'. Then she realises that 'The Duke' really just wants to recite poetry to her. And Satine drops her act, and starts singing along with Christian. The belt out a love melody and Satine is falling for him, amazed that a Duke could be so loving and sensitive. As they finish their song, Satine tells Christian that she is in love with him and his title doesn't matter. Christian retorts, telling her he is not a Duke. Satine's world comes crashing down as she realizes that she has made a huge mistake. To make matters worse, the Duke is waiting for her. Her calm exterior is replaced by fear as she orders Christian to hide, as she fears the repercussions of the Duke seeing them together.
Christian hides, and waits for her to finish. He helps Satine charm the Duke by reciting his poetry to her, ans she says it to the duke, but as she says the words, her eyes wander to Christian. The Duke in enamoured with her, Satine bluffs and says to the Duke that they should wait for the play to finish before they have sex. The Duke leaves for a few minutes, to return to her waiting for him.
Satine is devastated, the actual Duke is the typical pompous Duke, and she is angry with Christian for tricking her. But suddenly, she faints again. The Duke returns to find Christian and Satine on the bed, and he is angry, luckily Satine awakes and tells him that they are rehearsing for the play.
Satine and Christian invent the play on the spot, and Satine is impressed with his skill. With the help of Christians friends, they put on a rehearsal for the Duke and he is also impressed, but mostly with Satine. The Duke invests, and he requests that Satine is a part of their transaction.
Satine suspects the Dukes feelings for her, but she and Christian start to fall in love. The write the play together, and create a play-within-the-play where the Maharajah, The Courtesian and The Sitar Player represent The Duke, Satine and Christian respectfully. The play ends with the Courtesian and The Sitar player falling in love. Christian creates a song 'You Song' for her, and they are in love. Satine and Christian set about rehearsing the play, and use the Dukes money to fund their dreams.
The Duke starts to suspect their relationship after Satine cruelly rebukes him for Christian one night. He orders the play to be charged so that Satines character will choose the Dukes character over Christian. Realising that she has been too carefree about her relationship with Christian, she agrees to meet him privately and discuss the play.
She passes out again, and is unable to meet the Duke, Zidler bluffs for her after he learns that Satine is dying, and does not have much time left. Zidler does not tell Satine this.
Satine goes to meet the Duke the next night, to persuade him to keep the original ending, and it turns sour after Satine sees Christian and longingly gazes at him, halfway through seducing the Duke. He gets very angry, as he believed that she loved him. He abuses her and is only stopped by Chocolat. Satine flees the Dukes house, and goes back to Christian. They agree to leave the Moulin Rouge forever.
Satine goes to her room to get her things, until she is spotted by Zidler. He tells her that she is dying, and that the Duke is insanely jealous, and will have Christian killed if he sees them together. Satine attempts to be defiant, but realizes that she is trapped. At Zidlers coaxing, she realizes she must break-up with Christian, and live the remainder of her life with the Duke, in order to save Christian.
So she goes to Christian and breaks up with him. He doesn't believe her. It is only when she says that the Courtesan chooses the Maharajah that he sees that she is serious. He is devastated.
Satine returns to the Moulin Rouge to perform and sleep with the Duke, depressed and alone. Then suddenly Christian appears onstage, wishing to hurt Satine as she had hurt him. He throws money at her and states that he has paid his whore, Satine is devastated. She realizes that all her efforts to save Christian were in vain as she sees the Duke is signaling for his henchman to shoot him. She wants him to leave, but as he does, changes her mind. She knows that she is dying, and forgets about everything else besides Christian.
She starts singing Come What May, and then her and Christian re-unite onstage. The play is a roaring success, and the Duke's plans to shoot Christian are thwarted. They kiss and as the curtain falls, Satine dies in his arms, finally succumbing to her illness.
Although she died, she did not die alone, but in the arms of the one she loved, and she finally got the chance to experience real love for the first time -- the thing she needed most in the world, and the power that made her transform.