In the sweltering summer of 1937, Eugene Jerome is on the verge of entering adolescence, living in a lively Jewish-American household in Brighton Beach with his parents, Kate and Jack. The household includes Jack's sister, Blanche Morton, along with her two daughters: the stunning 16-year-old Nora and the delicate 13-year-old Laurie. Also living under the same roof is Eugene's older brother, Stanley, who works tirelessly at a men's hat shop. This bustling family is held together by the combined efforts of Jack, who juggles multiple jobs to provide for his loved ones, and Stanley's modest income.
However, each family member grapples with their own struggles, casting shadows over the household's atmosphere. Eugene, enthralled by baseball and filled with adolescent urges, becomes fixated on the alluring prospect of glimpsing a beautiful young woman unclothed, obsessively spying on Nora and a sultry neighbor who captures his youthful imagination.
Compounding the family's challenges, Jack's health takes a turn for the worse, forcing him to give up his second job as a cab driver and ultimately leading him to stop working altogether in order to focus on his recovery. As international tensions rise in pre-World War II Europe, Jack grows increasingly worried for his cousin and other family members still living in Poland, heightening his sense of dread. Meanwhile, Stanley, trapped in a job that offers him no fulfillment, is paralyzed by the thought of quitting, fearing the financial strain it could inflict on the family—especially with Jack's health already precarious.
On her own part, Kate becomes increasingly frazzled trying to juggle the obligations of caring for Blanche, who is struggling with personal issues of her own. Blanche finds herself torn between her lingering affection for Frank Murphy, the Irish neighbor prone to a few too many drinks, and the heartache of losing her husband. As she struggles to nurture her daughters, particularly Nora—who is bursting with aspirations of a Broadway career thanks to an upcoming audition—Blanche faces the daunting task of putting her foot down and delaying Nora's dream until she finishes high school.
The situation escalates as Frank extends an invitation to Blanche for a night out, but Kate disapproves, threatening to ruin the night. Nora, angered by her mother's restrictions, decides to make a rebellious escape from home, leaving Blanche in tears as she prepares for her date. Just when romance seems in reach, the Murphys receive devastating news: Frank has been in a serious car accident while drunk, now facing potential legal troubles and an uncertain future.
As the Murphys navigate the fallout, Stanley confesses to Kate that he has squandered his entire paycheck in an attempt to cover the family's expenses tied to Jack's dwindling income. Feeling hopeless, Stanley initially considers leaving home for military service but ultimately chooses to stay and support his father out of love.
The friction between Kate and Blanche boils over, with Blanche making the decision to seek independence by securing a new job and apartment and planning to bring her daughters to stay with her when the time comes.
Meanwhile, the tensions ease as Nora and Stanley return home, finding comfort in the familiarity of their parents after a brief separation. Kate and Blanche reach a reconciliation, with Kate suggesting that Blanche stay until she can find work and even proposing that she take over the Murphys' soon-to-be-vacant apartment across the street.
As the dynamics of the Jerome household shift, Stanley shows his gratitude to Eugene by gifting him a provocative photograph. The exciting news that Jack's relatives from Poland are soon to arrive sends the family into a frenzy as they prepare to welcome these new additions to their already bustling home.
