Jurgis Rudkus marries his fifteen-year-old sweetheart, Ona Lukoszaite, in a joyous traditional Lithuanian wedding feast. They and their extended family have recently immigrated to Chicago due to financial hardship in Lithuania (then part of the Russian Empire). They have heard that America offers freedom and higher wages and have come to pursue the American Dream.
Despite having lost much of their savings being conned on the trip to Chicago, and then having to pay for the wedding—and despite the disappointment of arriving at a crowded boarding house—Jurgis is initially optimistic about his prospects in Chicago. Young and strong, he believes that he is immune to the misfortunes that have befallen others in the crowd. He is swiftly hired by a meatpacking factory; he marvels at its efficiency, even while witnessing the cruel treatment of the animals.
The women of the family answer an ad for a four-room house; Ona, who came from an educated background, figures that they could easily afford it with the jobs that Jurgis, proud Marija, and ambitious Jonas have gotten. While they discover at the showing that the neighborhood is unkempt and the house doesn't live up to the advertisement, they are taken in by the slickness and fluent Lithuanian of the real estate agent and sign a contract for the house.
However, with the help of an old Lithuanian neighbor, they discover several unexpected expenses in the contract that they must pay every month on time, or else face eviction—the fate of most home buyers in the neighborhood. To meet these costs, Ona and thirteen-year-old Stanislovas (whom the family had wished to send to school) must take up work as well.
While sickness befalls them often, they cannot afford not to work. That winter, Jurgis's father, weakened by exposure to chemicals and the elements at his job, dies of illness.
Some levity is brought to their lives by the arrival of a musician, named Tamoszius, who courts Marija, and the birth of Jurgis and Ona's first child. However, this happiness is tempered when Ona must return to work one week after giving birth, and Marija is laid off in a seasonal cutback. Jurgis attends union meetings passionately; he realizes that he had been taken in by a vote-buying scheme when he was new to Chicago, learns that the meat factories deliberately use diseased meat, and furthermore that workers frequently come down with ailments related to their dangerous and unsanitary work.
Work becomes more demanding as wages fall; the working members of the family suffer a series of injuries. Amid this hardship, Jonas deserts the family, leaving them no choice but to send two children to work as newspaper boys. The youngest child, a handicapped toddler, dies of food poisoning; only his mother grieves his death.
After recovering from his injury, Jurgis takes the least desirable job at a fertilizer mill. In misery, he begins drinking alcohol. He becomes suspicious of his pregnant wife's failure to return home on several nights. Ona eventually confesses that her boss, Phil Connor raped her, after which, by threatening to fire and blacklist everyone in her family, he managed to coerce her into a continuing sexual relationship.
Jurgis furiously attacks Connor at his factory, but half a dozen men tear him away. While in prison awaiting trial, he realizes it is Christmas Eve. The next day, his cellmate, Jack Duane, tells him about his criminal ventures and gives him his address. At trial, Connor testifies that he had fired Ona for "impudence" and easily denies Jurgis's account; the judge dismissively sentences Jurgis to thirty days in prison plus court fees.
Stanislovas visits Jurgis in prison and tells him of the family's increasing destitution. After Jurgis serves his term (plus three days for his inability to pay the fees), he walks through the slush for an entire day to get home, only to find that the house had been remodeled and sold to another family. He learns from their old neighbor that, despite all of the sacrifices they had made, his family had been evicted and had returned to the boarding house.
Upon arriving at the boarding house, Jurgis hears Ona screaming. She is in premature labor, and Marija explains that the family had no money for a doctor. Jurgis convinces a midwife to assist, but it is too little too late; the infant is dead, and with one last look at Jurgis, Ona dies shortly afterward. The children return with a day's wages; Jurgis spends all of it to get drunk for the night.
The next morning, Ona's stepmother begs Jurgis to think of his surviving child. With his son in mind, he endeavors again to gain employment despite his blacklisting. For a time, the family gets by and Jurgis delights in his son's first attempts at speech. One day, Jurgis arrives home to discover that his son had drowned after falling off a rotting boardwalk into the muddy streets. Without shedding a tear, he walks away from Chicago.
Jurgis wanders the countryside while the weather is warm, working, foraging, and stealing for food, shelter, and drink. In the fall, he returns to Chicago, sometimes employed, sometimes a tramp. While begging, he chances upon an eccentric rich drunk—the son of the owner of the first factory where Jurgis had worked—who entertains him for the night in his luxurious mansion and gives him a one-hundred-dollar bill (worth about $3000 today). Afterward, when Jurgis spends the bill at a bar, the bartender cheats him. Jurgis attacks the bartender and is sentenced to prison again, where he once again meets Jack Duane. This time, without a family to anchor him, Jurgis decides to fall in with him.
Jurgis helps Duane mug a well-off man; his split of the loot is worth over twenty times a day's wages from his first job. Though his conscience is pricked by learning of the man's injuries in the next day's papers, he justifies it to himself as necessary in a "dog-eat-dog" world. Jurgis then navigates the world of crime; he learns that this includes a substantial corruption of the police department. He becomes a vote fixer for a wealthy political powerhouse, Mike Scully, and arranges for many new Slavic immigrants to vote according to Scully's wishes—as Jurgis once had. To influence those men, he had taken a job at a factory, which he continues as a strikebreaker. One night, by chance, he runs into Connor, whom he attacks again. Afterward, he discovers that his buddies cannot fix the trial as Connor is an important figure under Scully. With the help of a friend, he posts and skips bail.
With no other options, Jurgis returns to begging and chances upon a woman who had been a guest to his wedding. She tells him where to find Marija, and Jurgis heads to the address to find that it is a brothel being raided by the police. Marija tells him that she was forced to prostitute herself to feed the children after they had gotten sick, and Stanislovas—who had drunk too much and passed out at work—had been eaten by rats. After their speedy trial and release, Marija tells Jurgis that she cannot leave the brothel as she cannot save money and has become addicted to heroin, as is typical in the brothel's human trafficking.
Marija has a customer, so Jurgis leaves and finds a political meeting for a warm place to stay. He begins to nod off. A refined lady gently rouses him, saying, "If you would try to listen, comrade, perhaps you would be interested." Startled by her kindness and fascinated by her passion, he listens to the thundering speaker. Enraptured by his speech, Jurgis seeks out the orator afterward. The orator asks if he is interested in socialism.
A Polish socialist takes him into his home, conversing with him about his life and socialism. Jurgis returns home to Ona's stepmother and passionately converts her to socialism; she placatingly goes along with it only because it seems to motivate him to find work. He finds work in a small hotel that turns out to be run by a state organizer of the Socialist Party. Jurgis passionately dedicates his life to the cause of socialism.
Panorama of the beef industry in 1900 by a Chicago-based photographer
