The animal-tamer shows off his menagerie, reserving till last his prize specimen: the serpent - Lulu in a pierrot costume.
SCENE 1: The painter's studio
Dr Schön watches as the painter works on the portrait of Lulu in the pierrot costume. Alwa Schön comes to takes his father to a rehearsal at his theatre, expressing surprise that Lulu's husband, a professor of medicine, is not present - as Dr Schön says, he rarely lets her out of his sight.
Left alone with Lulu, the painter tries to embrace her, but she eludes him by running round the studio. When he catches up with her, she is unresponsive. Lulu's husband, coming to fetch her, realises from the wrecked studio what has been happening, starts to accuse them, but dies of a heart attack.
The painter is appalled by Lulu's apparent lack of concern and by her lack of belief in anything, but remains totally obsessed by her.
SCENE 2: An elegant drawing room in the home of Lulu and the painter
Lulu's portrait in the pierrot costume hangs on a wall
The painter receives news of the sale of another painting of Lulu - he feels that she has brought him luck. They also receive the official announcement of Dr Schön's engagement to a young lady he has been courting for some time. As he goes to work in his studio, the painter admits Schigolch, a shady figure from Lulu's past, whom he takes for a beggar, who is paying her a visit for the first time in her new home. He borrows some money from her and is pleased to find her in such luxury. He leaves as another visitor arrives, Dr Schön, who tells Lulu he is surprised her husband allows Schigolch to visit. He has come to beg her to refrain from visiting him, now that he is officially engaged - he has made a good marriage for Lulu and wants her out of his life. He is surprised that her husband does not keep her in hand, but she answers that her husband is completely unaware of her true nature - Schön is the only man she has ever belonged to, ever since he rescued her from the streets when she tried to steal his watch.
The painter returns from his studio and Lulu leaves angrily, telling him that she has been discarded. The painter is puzzled and Schön decides that he must know something about Lulu if their marriage is to succeed. He reveals that he has known her since she was a child selling flowers in the street and that he had introduced her to her first husband when his own wife died and Lulu's presence was standing between him and the respectable marriage he planned.
The painter realises that the version of her life Lulu has given him is completely false, including the impression she has conveyed that she had never loved anyone and the story that her father had died in a madhouse, whereas, Schön tells him, Schigolch is her father. Lulu's past, he reveals, is far from respectable.
Overwhelmed, the painter staggers into the next room and locks the door. When groaning is heard Schön tries to break open the door. Lulu comes back and he tells her to fetch an axe.
Alwa appears with the news that a revolution has broken out in Paris and no one at his father's newspaper knows what to write. They succeed in breaking down the door, to find that the painter has cut his throat.
Schn rings the police, appalled at Lulu's apparent calm. She answers that he will end up by marrying her.
SCENE 3: A dressing-room in a theatre
Lulu is about go go on stage and dance, to music of Alwa's composition. Schön has got her a job in the theatre in his attempt to be free of her, hoping that she will find another husband. She has succeeded in attracting the interest of a prince, who, she tells Alwa, wants to take her to Africa. Alwa remembers the first time he saw her and how he had even respected her more than his dying mother, so much so that after his mother's death he had told his father that he should marry Lulu. Shortly after she goes on stage there is a commotion and she is carried back. She had fainted at the sight of Dr Schön and his future bride. Schön comes backstage and orders her to go back, but she refuses to dance before his fiancee.
Their quarrel ends in his realisation that he is tied to Lulu and cannot marry another. Lulu triumphantly dictates a letter for him in which he breaks off the engagement. He writes with the conviction that it is his death warrant.
SCENE 1: A magnificent room in Dr. Schön's house
The portrait is there, in a new frame
Countess Geschwitz, herself in mannish costume, begs Lulu to dress as a man for the female artists' fancy dress ball to which she has invited her that night. Dr Schön, now married to Lulu, feels that his life is in ruins. Lulu wants him to take her for a drive, but he is due back at the stock exchange.
As they leave the room, the countess creeps back in and hides, followed by Schigolch and Rodrigo, who is carrying a schoolboy, who wishes to express his passion for Lulu by reading her a poem. Rodrigo says that he wants to marry Lulu and Schigolch admits that he, too, would have liked to marry her - and that he certainly is not her father. Lulu entertains them, as she does every stock exchange day. Alwa arrives and Rodrigo and the schoolboy hide. Shigolch moves more slowly and Alwa sees him. Lulu hastily explains that he is a friend of his father's. Dr Schön returns unannounced and watches from a gallery as Lulu entertains his son.
She is grateful to Alwa for the way he has always supported her, but when he begins to confess to loving her, she tells him that she poisoned his mother. Dr Schön, now aware of the presence of Schigolch and Rodrigo, makes his own presence known and begins to berate Lulu, becoming more paranoid as he discovers Geschwitz.
He hands Lulu a gun, demanding that she kill herself. She begs for mercy, declaring that she has never tried to appear as other than she really is. As the schoolboy springs from his hiding palce, Schön is distracted, and Lulu turns the gun on him and kills him. Despite Lulu's entreaties and promises to be faithful to him, Alwa calls the police.
During an orchestral interlude, a silent film shows Lulu's trial, condemnation and imprisonment.
SCENE 2: The same as the previous scene, but neglected and dusty
The portrait is turned to the wall
Alwa, Countess Geschwitz, Schigolch and Rodrigo have planned Lulu's escape. The countess, having infected herself and Lulu with cholera so that they were in adjoining beds in hospital, is about to go back and switch places with Lulu. Rodrigo, now pretending to be Alwa's servant, is to marry Lulu, take her with him to Paris and use her in a double circus act.
When Schigolch escorts Geschwitz to the hospital, the schoolboy arrives with a plan to help Lulu escape, but they convince him that she has died of cholera.
When Schigolch brings Lulu back, Rodrigo is so disugusted by her emaciated form that he refuses to have anything to do with the plan. Alwa finds Lulu no less beautiful than before and even her reminders that she shot his father and that they are on the couch where he bled to death fail to quell his ardor.
SCENE 1: A gambling salon in Paris run by Alwa and Lulu
The portrait is on the wall
In the midst of gambling and talk of the latest hot shares, one of the guests, a marquis, tries to blackmail Lulu, telling her that he knows of her past, and demanding money if she refuses his offer of a position in a brothel in Cairo.
Rodrigo also tries to blackmail her, so she gets Schigolch to kill him, engaging the devoted Countess Geschwitz, to whom she has just been very unkind, to assist in the project by luring him to Shigolch's lodging on the pretext that she is desperate for him to make love to her. It is discovered that the prized shares are now worthless and Alwa, along with most of the guests, has lost his money.
Lulu changes clothes with a groom and when the police arrive, she has escaped.
SCENE 2: London, a dingy attic
Lulu is now obliged to try her luck as a prostitute to keep herself, Alwa and Schigolch. Her first client is a professor who does not speak.
Countess Geschwitz arrives. She has been trying unsuccessfully to raise some money, but brings the portrait of Lulu which she had cut out of its frame before leaving Paris. Lulu is horrified at this reminder of her past beauty, but Alwa understands again the power which is driving him and hangs it on the wall.
Lulu brings back a negro, but they quarrel about payment. Alwa intervenes and the negro strikes him dead with a cudgel. Schigolch goes to the pub, and Countess Geschwitz is looking at the portrait, trying to find the strength to leave Lulu, when she brings in her last client, Jack the Ripper. He has little money, but Lulu begs him to stay with her, and even pays him. They go to her room, where he kills her. He emerges and kills Geschwitz, whose last cry is one of devotion to Lulu.