As the novel opens, Jimmie, a young boy, is leading a street fight against a troop of youngsters from another part of New York City's impoverished Bowery neighborhood. Jimmie is rescued by Pete, a teenager who seems to be a casual acquaintance of his. They encounter Jimmie's offhandedly brutal father, who brings Jimmie home, where we are introduced to his timid older sister Maggie and little brother Tommie, and to Mary, the family's drunken, vicious matriarch. The evening that follows seems typical: the father goes to bars to drink himself into oblivion while the mother stays home and rages until she, too, drops off into a drunken stupor. The children huddle in a corner, terrified.
As time passes, both the father and Tommie die. Jimmie hardens into a sneering, aggressive, cynical youth. He gets a job as a teamster. Maggie, by contrast, seems somehow immune to the corrupting influence of abject poverty; underneath the grime, she is physically beautiful and, even more surprising, both hopeful and naïve. When Pete--now a bartender--makes his return to the scene, he entrances Maggie with his bravado and show of bourgeois trappings. Pete senses easy prey, and they begin dating; she is taken--and taken in--by his relative worldliness and his ostentatious displays of confidence. She sees in him the promise of wealth and culture, an escape from the misery of her childhood.
There comes a night when the drunk and combative Mary accuses Maggie of going "to deh devil" and disgracing the family; Maggie runs into Pete's arms, and we are given to understand that the two are, indeed, sleeping together. Jimmie is furious that Pete has "ruined" his sister, and he gets very drunk with a friend and gets into a brawl with Pete. After this, Maggie leaves home and goes to live with Pete. Jimmie and Mary affect sorrow and bewilderment at Maggie's fall from grace, and her behavior becomes a neighborhood scandal. A scant few weeks after Maggie leaves home, she is in a bar with Pete when they meet Nellie, a scheming woman with a veneer of sophistication who has no trouble convincing Pete to leave Maggie. Abandoned, Maggie tries to return home, but her family rejects her.
The linear narrative now ceases, and we are given a series of scenes, arranged in chronological order but separated by passages of time. There is an interlude in which we see that Jimmie, who acts horrified at Maggie's actions, has in fact himself seduced and then abandoned at least one girl. In another brief scene, Maggie visits Pete at work, and he, too, refuses to acknowledge her legitimate claims on him. Months later, we are shown a prostitute--presumably Maggie, but unnamed--walking the streets of New York, pathetic and rejected, bound for trouble. There is a scene with Pete in a bar, badly drunk and surrounded by women; he collapses on the floor and, in his turn, is abandoned by the scornful and manipulative Nellie. Finally, the novel ends with Jimmie giving Mary the news that Maggie's dead body has been found. Mary stages a scene of melodramatic mourning for her ruined child, which ends with her deeply hypocritical and bitterly ironic concession: "I'll fergive her!"