SCENE 1: Catfish Row, a former mansion of the aristocracy, now a Negro tenement, on the waterfront in Charleston, South Carolina
It is evening. Clara sings a lullaby to her child. Serena tries to stop her husband, Robbins, from joining a crap game. Clara's husband Jake, a fisherman, sings to the baby. Porgy, a cripple who uses a goat-cart to get around, joins the group of crap players, turning aside accusations that he is "soft" on Bess, the girlfriend of Crown, a tough stevedore. Crown, already drunk, arrives with the flashily dressed Bess on his arm and joins the game, and not only keeps on drinking but buys "happy dust" from Sportin' Life, the local drug pedlar.
A fight breaks out and Crown kills Robbins. As he leaves to hide from the police, he warns that if Bess takes up with anyone else, it will only be only temporary - he will be back for her.
A shaken Bess buys happy dust from Sportin' Life, but refuses his offer to take her to New York. Everyone slams the door in her face, but Porgy takes her in.
SCENE 2: Serena's room
Robbins' body lies on a bed, with a saucer on his chest into which friends are putting money to pay for the funeral. Serena at first refuses Bess' money, but accepts when she explains that it is now Porgy, not Crown, who gives her money.
The police take away one of the mourners, first accusing him of the murder; then, when he says it was Crown who did it, of being a material witness. They warn Serena that unless Robbins is buried soon, his body will be handed over to medical students. The undertaker, at first de-claring that the $15 collected is not enough, eventually agrees to bury Robbins and accept payment later. Bess leads the mourners in a spiritual.
SCENE 1: Catfish Row
Jake and other fishermen sing as they repair netting. One of the women reminds them that it is picnic day, and Jake arranges for the men to go fishing the next day, ignoring Clara's fears that the September storms are imminent. As Porgy expresses his new-found joy in life, the women comment that a girl like Bess is not likely to make him happy, being more suited to a killer like Crown.
Maria, keeper of the cook-shop, attacks Sportin' Life for peddling dope round her shop. Frazier, a crooked lawyer, charges Porgy money to di-vorce Bess from Crown, claiming that the fact that she is not actually married to him makes the divorce even more expensive. A buzzard flies over, arousing Porgy's superstitious fears. Sportin' Life tries to sell Bess dope, but she refuses angrily and Porgy warns him to keep away. Porgy and Bess affirm that she now belongs to him.
The residents of Catfish Row come out ready for the picnic. Maria persuades Bess, who had intended staying home with Porgy, to come too.
SCENE 2: Kittiwah Island
Sportin' Life entertains the picnic party with a song, It Ain't Necessarily So, casting doubts on stories in the Bible and angering Serena with his irreverence.
The boat whistles, indicating that it is time to leave and Bess, lagging behind, is intercepted by Crown, who has been hiding out on the island. She tries to insist that she is now respectable and living with Porgy, but he overcomes her resistance, partly by force and partly by physical attraction.
SCENE 3: Catfish Row
Jake and his crew set off for the fishing, ignoring warnings that a storm is coming.
Bess arrives back, delirious, after having taken a week to make her way back on foot from the island. Porgy puts her to bed, nervous of taking her to a hospital. Serena prays for her and Bess is restored to her right mind. Porgy knows that she has been with Crown, but forgives her. She assures him she wants to stay with him, though still fearing Crown's power over her.
Maria tries to reassure Clara, but the hurricane bell rings and the wind rises.
SCENE 4: Serena's room
Everyone has taken refuge from the storm, trying to drown its noise with singing. Crown bursts in to claim Bess and laughs when Porgy tries to defend her. He scandalises Serena by defying God and the storm. Clara sees Jake's boat upside down in the river and gives her baby to Bess to hold as she runs out. Bess cries out that a man should go with her and Crown, after challenging Porgy, goes out himself.
SCENE 1: Catfish Row
The storm is over, and Jake, Clara and Crown are assumed to be dead, though Sportin' Life throws doubt on the death of Crown. Crown comes back, but as he passes under Porgy's window, Porgy first knifes him, then leans out and strangles him, unseen by anyone.
SCENE 2: Catfish Row
A detective and coroner come to investigate Crown's murder. Serena and her friends swear that she has been in bed for three days and knows nothing. They question Porgy, only wanting him to identify the body, but Porgy is afraid.
When the detective and coroner have gone, promising to send someone to fetch him, Sportin' Life convinces him that the dead man's body will bleed in the presence of his killer. A policeman drags out the terrified Porgy. Sportin' Life tries to convince Bess that Porgy will be locked up and to persuade her to take some happy dust and come with him to New York. Almost against her will, she takes one lot of dope and he leaves the other, sure she will take it.
SCENE 3: Catfish Row, a week later
Porgy is brought home, having been kept in jail for contempt of court for keeping his eyes closed and refusing to look at Crown's face. He has brought presents for everyone, but the people move away in embarrassment. It is not until he sees Serena holding Clara's baby that he realises Bess is not there.
They tell him she has gone to New York, and he calls for his goat and sets off to find her.