A week has passed since the last act. The household is in chaos because Jack has suffered a heart attack and is recuperating at home. Meanwhile, Blanche is preparing for her date with Frank Murphy. Stanley sneaks into the house to speak with Eugene in their room. Stanley confesses that he lost his entire week's salary playing poker and is in a state of desperation.

Jack decides to get up and go downstairs to meet Blanche's date. Kate is horrified by her husband's disregard for his health, leading to an argument between them. Nora comes downstairs and leaves for her date, avoiding her mother. Blanche appears, and everyone thinks she looks like a movie star. Jack sends Eugene and Laurie to get ice cream. Kate goes upstairs to ask Stanley for his pay so she can give emergency money to Blanche. Stanley admits that he lost the money in a poker game. Kate tries to stay calm and chooses not to tell anyone about it for the time being.

Kate returns to the kitchen in a highly agitated state. Blanche is still preoccupied with worries about Nora. Kate becomes angry at Blanche for focusing only on her own problems. The sisters get into a fight, which is interrupted by Laurie's return. Laurie brings a note from Frank Murphy's mother, explaining that Frank had a car accident and is in the hospital, so he cannot keep the date. This news sparks another argument between Kate and Blanche. Kate expresses long-held resentment towards Blanche, stemming from their childhood. Blanche decides she will move out and stay with a friend while she looks for a job. She tells Kate that once she has a job, she will take her daughters and move into her own home.

Eugene is sent upstairs to fetch Stanley and Laurie for dinner. Stanley demands money from Eugene in case he has to sleep out that night. Stanley has decided to join the Army, hoping to earn more money that way. Eugene is very upset, but Stanley leaves anyway. Eugene cannot bring himself to tell the family where Stanley has gone during dinner. After the meal, he confides in Laurie.

Later that night, Blanche waits outside for Nora to return. Blanche tells Nora about her decision to move out. Nora expresses that she feels Blanche cares more for Laurie than for her. They make an uneasy peace. Kate comes downstairs due to the noise and asks Blanche not to leave. Kate persuades Blanche to stay while she looks for work.

The following day, Stanley returns just in time for dinner. He informs the family that he passed the physical examination but couldn't enlist because the family needed him at home. Stanley and Jack have a conversation. Stanley reveals that he earned some money at a bowling alley and hands it over to his mother, promising to make up the remaining amount. Jack then mentions that war is imminent.

Upstairs, Stanley gives Eugene a gift: a postcard featuring a naked woman. Eugene is astonished. Meanwhile, Jack receives a letter stating that his cousin and their family have escaped from Poland and are heading to New York City. He starts planning how to accommodate the additional family members in the house.