Tragic naturalistic drama set in the seamy milieu of a tenement house in New York where the emotions of the inhabitants are inflamed by the heat of summer. The brutal Joneses, the good-natured Fiorentinos, and the old intellectual Mr. Kaplan are neighbours of the unhappy Maurrants. Mrs. Maurrant, the talk of the neighbourhood, has been carrying on with Sankey, the local milk-bill collector. Her daughter Rose fears Maurrant's discovery of the affair and urges her mother to be more discreet. But Mrs. Maurrant meets once too often with her lover, and Maurrant shoots them to death.
Returning from her mother's deathbed at the hospital, Rose says goodbye to her young admirer Sam Kaplan, whose bigoted sister has thwarted the innocent love between them. Rose accepts this frustration just as she has accepted the tragic fate of her parents. She leaves Sam and the tenement house, avowing her new faith that love will come out of self-knowledge. Life goes on in the tenement as new people move into the vacated apartment.