Scene 4 begins with an altercation between Mr. Shu Fu, the barber, and Wong, who has been trying to sell water to Shu Fu's customers. Shu Fu chases Wong out of his shop and hits his hand with a hot curling iron, burning it badly. The unemployed man from the first scene and Mrs. Shin are witnesses out in the street. They advise Wong to go to the police to report the crime.
Shen Te enters; she is on her way home from Yang Sun's house, where she has spent the night. She gives a monologue about how beautiful Setzuan seems in the morning, delivers rice to the people waiting outside her tobacco shop for free handouts, and goes into a carpet shop owned by the old woman and the old man. While she is inside, Shu Fu speaks of his growing love for her. Shen Te exits and pays the old woman and the old man for the shawl she has purchased at their carpet shop. The old woman offers to loan Shen Te two hundred silver dollars so she can pay her rent.
Mrs. Shin points out Wong's injured hand to Shen Te; Shen Te says he should go to a doctor, but the unemployed man thinks he should go to a judge instead to seek compensation. When Wong looks around for people who would be a witness, nobody is willing to volunteer. Shen Te is appalled and says that if no one else will speak up, she will perjure herself and say that she was a witness. Disgusted with the others, she yells at them to go away.
Mrs. Yang, Yang Sun's mother, enters and tells Shen Te that her son has been offered a job from the director of the airfield in Peking, but that he needs to pay five hundred silver dollars for it. Shen Te pledges to try to help Yang Sun. Scene 4a consists of "The Song of Defenselessness," in which Shen Te sings first as herself, then with her Shui Ta mask on.
Scene 5 begins with Mrs. Shin explaining to Shui Ta, who takes no notice, that the barber Shu Fu has expressed interest in marrying Shen Te. Yang Sun enters and interacts with Shui Ta, having no idea he is actually talking to his lover, Shen Te. He considers how long it will take to raise the rest of the five hundred silver dollars (Shen Te has already given him the two hundred loaned to her by the old woman), and insults Shen Te to Shui Ta.
Mrs. Mi Tzu enters and Shui Ta says he would like to sell his tobacco stock to help his cousin, Shen Te, marry Yang Sun. Yang Sun demonstrates yet again that he has no interest in Shen Te's financial well-being or her ability to pay the old couple back; he just wants to get to Peking to fly again. After Shui Ta has agreed to sell the tobacco, Yang Sun reveals that his plan is to betray Shen Te: "I'm leaving her behind. No millstones round my neck!" When he leaves, Shui Ta bursts out as Shen Te, "I've lost my shop! And he doesn't love me!"
Mr. Shu Fu enters and tells Shui Ta that he would like to offer Shen Te the run of some cabins on his property and other gifts so that she can continue being kind to everyone. Wong and the policeman enter, and Shui Ta betrays Wong (but tells the truth) in saying that his cousin was not present at the time of the assault with the curling iron. Shui Ta has let Wong use Shen Te's new shawl as a sling, implying that her affair with Yang Sun is over so she no longer has a need to impress him with beautiful things. Shui Ta runs off to "find" his cousin, and Shu Fu explains his good intentions toward Shen Te to the audience.
Yang Sun returns and Shu Fu tells him that he and Shen Te are about to announce their engagement. Just then, Shen Te emerges from the back room. When Yang Sun reminds her of how he loves her, she says, "Forgive me, Mr. Shu Fu, I want to go with Mr. Yang Sun." She proves Yang Sun's rude characterization of her correct by ignoring the horrible things he said about her to Shui Ta. They exit as she sings to the audience, "I don't want to know if he loves me / I want to go with the man I love."
Scene 5a consists of Shen Te explaining to the audience, "Something terrible has happened." She is in a wedding dress on her way to wed Yang Sun, but says that right after she left the tobacco shop in the previous scene, she ran into the old woman. The old woman had to ask for her two hundred silver dollars back, since the anxiety of having loaned them made her husband ill. She said she would.
The theme of love as a weakness is emphasized with regard to Shen Te and Shu Fu in the beginning of Scene 4. Shen Te is walking home from Yang Sun's house and everything seems pleasant to her because she is, as she says, in love: "They say you walk on air when you're in love but it's even better walking on the rough earth, the hard cement." In Scene 4, Yang Sun will reveal to Shui Ta that he plans to abandon Shen Te and take her money. After he leaves, Shui Ta says, "One weakness is enough, and love is the deadliest." Meanwhile, Shu Fu speaks of his love for Shen Te for the first time: "I begin to suspect I am in love with her. She is overpoweringly attractive!"
The old woman is a candidate for a "good" person, and Shen Te recognizes that when she offers to lend her money to pay her rent. Shen Te says, "I wish the gods could have heard what your wife was just saying, Mr. Ma. They're looking for good people who're happy - and helping me makes you happy because you know it was love that got me into difficulties!"
Shen Te sings a lot in these scenes. When nobody will step forth as a witness to Wong's assault, she sings that she will say she saw it. This song is available to the other characters, and Mrs. Shin responds to it. Shen Te's next two songs acts as commentary on the people around her, to the audience: "They've stopped answering... nothing can make them look up / but the smell of food" and "Yang Sun, my lover: ...bringing to friends in faraway lands / the friendly mail!"
Scene 4a, which consists of "The Song of Defenselessness," demonstrates the theme of Patriarchal Capitalism. Shen Te sings first with Shui Ta's mask in her hand, then as Shui Ta, with the mask on. The first part of the song is an appeal to the gods, pointing out that "even the gods are defenseless" and asking, "Why don't the gods to the buying and selling"? As Shui Ta, she is more cynical: "You can only help one of your luckless brothers / by trampling down a dozen others."
The issue of gender comes to the forefront during Scene 4, when Yang Sun interacts with Shui Ta in a completely different manner than that in which he interacts with Shen Te. Shui Ta defends his cousin (himself) by saying, "She is a human being, sir! And not devoid of common sense!" However, Yang Sun answers, "Shen Te is a woman: she is devoid of common sense. I only have to lay my hand on her shoulder, and church bells ring."