When John Pope, Sr., the opinionated, bellicose patriarch of the Pope family, comes to New York to visit his sons Polo and Johnny in their Lower East Side housing project, he finds Johnny, his favorite, jumpy and overwrought, and bitterly voices his disappointment that Polo, his younger son, is working as a bouncer in a cocktail lounge. When Pop asks Polo to lend him $2,500 to renovate the bar that he has just bought in Florida, Polo informs him that the money has already been spent, prompting Pop to lash out and call Polo a bum. That night at the apartment the brothers share with Johnny's pregnant young wife Celia, Celia serves dinner to Johnny and Pop while Johnny anxiously glances out the window. As Johnny watches, three men meet at the street corner and then proceed to his apartment. The three, Mother, Chuch and Apples, are Johnny's drug connections, and when they ring the doorbell, Johnny lies that they are his poker buddies and steps out in the hallway to beg Mother to advance him some heroin. Johnny, who became addicted while recovering from wounds he suffered during the Korean War, now needs a fix three times daily. Refusing to supply Johnny with any more drugs until he pays for those he had previously bought on credit, Mother hands him a gun and suggests that he steal the money. Once Pop leaves, Johnny and Celia drop their façade of the happy family and Celia reproaches Johnny for his inability to communicate with her. Unaware of her husband's addiction, Celia believes that he is seeing another woman although he denies it. Soon after, Polo comes home, roaring drunk while Johnny, tormented by withdrawal symptoms, stumbles out to the street in search of drugs. Alone with Polo, Celia chastises him for fighting with his father, and Polo bitterly replies that Pop was never a father to them, having placed them in an orphanage when they were young boys. After Polo calls Johnny a loser, Celia tells Polo that she knows he is in love with her and asks him to move out. When Johnny, prowling the streets for victims to rob, fails to return home that night, Polo admits his love for Celia and wonders how she can live with his brother. Celia, neglected and confused, confesses that she no longer loves her husband and in desperation, came to Polo's bedroom door earlier that night but found herself unable to go in. After Celia leaves for work, Johnny returns home, shaking, and begs Polo for twenty dollars to buy some drugs. When Polo protests that has already given Johnny his life savings of $2,500, Johnny promises to quit once again. Johnny then invites Polo to join him for breakfast with their father, but Pop, holding a grudge, refuses to shake Polo's hand. Polo departs, and Johnny, in the throes of withdrawal, asks Pop to reconcile with him. After accusing Pop of never being a father to him, Johnny breaks down and Polo returns and hustles him into his car. When Polo tells Johnny that he plans to turn him in to the police, Johnny threatens to jump out of the moving vehicle. Polo relents and agrees to drive him to meet his drug dealer at a playground. The police have arrested the dealer, however, so Polo drives Johnny home, where Johnny, now delirious, hallucinates that he is in battle. Agonizing over his brother's condition, Polo begs Mother for a fix, and Mother tosses him a packet and then instructs him to sell his car to pay his brother's debt. After selling his beloved car, Polo takes Pop to a football game. When Celia comes home from work that night, she tells Johnny their marriage is over. Johnny, restored to his former self by the power of narcotics, shows Celia a dress he has bought for their unborn baby and begs her forgiveness. Celia embraces Johnny in relief, but when Polo returns, he insists that Johnny tell his wife he is an addict. Johnny is on the verge of confessing his secret when Pop buzzes the doorbell from downstairs. After Johnny finally admits that he is a junkie, Celia, in disbelief, reassures her husband of her love and support. Just then, Pop pounds at the door and the four sit down to a tension-filled dinner. As Pop chatters on, Johnny unemotionally states that he is a junkie. Wanting to blame someone, Pop explodes. After Johnny runs out of the apartment, Celia begins to experience spasms and Pop and Polo rush her to the doctor. Once the doctor assures them that Celia and the baby are well, Polo goes to look for Johnny. Johnny, meanwhile, returns to the apartment and finds Mother waiting there for his money. As Mother taunts Johnny about his addiction, Polo enters and repays him. Mother then tosses a packet of dope to Johnny, but Johnny throws it back and declares he is through, then begins to suffer withdrawal convulsions. After Mother leaves, Celia and Pop return and Celia insists that Johnny be hospitalized, over the objections of Pop and Polo. When Pop offers to stay in New York and take care of his son, Celia asserts that she will take care of Johnny by herself and contends that his only chance of survival is to notify the police. When Johnny consents, Celia phones the police department to report an addict and then bravely embraces her husband.