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One Third of a Nation (1939) movie poster

Plot Summary

One Third of a Nation (1939) Plot Summary Explained

Release, runtime and language
1939 · 79 mins · English
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Directed by
Dudley Murphy
Starring
Jeff Corey, Sidney Lumet, Myron McCormick, Sylvia Sidney, Percy Waram, Iris Adrian

The negligent owner of a tenement slum becomes romantically involved with one of the building’s residents.

On this page (6)
  1. 1 Where to watch
  2. 2 What happens: full plot
  3. 3 Plot questions answered
  4. 4 Movie threads
  5. 5 Movies like One Third of a Nation
  6. 6 Every angle
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Full plot summary · contains spoilers

What Happens in One Third of a Nation: Full Plot Summary

The whole story of One Third of a Nation (1939) explained, from the opening scene to the final frame: every key event, every twist and what it all adds up to. Read it as a quick recap before the sequel, to check a scene you missed, or to finally understand what really happened.

On a night when a fire roars through a run-down New York City tenement, a young boy named Joey Rogers scrambles toward a faulty fire escape that collapses, leaving him badly injured. His much older sister, Mary Rogers, rushes him to the hospital with the help of the wealthy Peter Cortlant, who covers the medical bills on the spot. Cortlant is informed by his trusted ally and business mind, Arthur Mather, that he actually owns the building where the fire occurred.

The local district attorney digs into the incident and explains that the tenement’s age makes it exempt from modern building safety codes. Since no tenants had previously lodged complaints, no crime is straightforwardly established. When Cortlant visits the burned site, he is warned to steer clear of Mary Rogers by her boyfriend, Sam Moon, a tension that foreshadows the social and personal ramifications of the case.

Mary learns of Cortlant’s ownership of the building and, frustrated by the situation, takes Joey out of the hospital. The boy, crippled and increasingly delusional, believes the building itself is speaking to him and he vows revenge on the tenement. In the meantime, Mary meets again with Peter Cortlant and persuades him to consider converting his decrepit properties into public housing and to rebuild them for the city’s benefit.

Cortlant’s cost concerns, however, weigh heavily. His sister, Ethel Cortlant, grows worried about the project and resorts to blackmail—threatening to reveal an alleged affair with Mary to the press in an effort to derail the plan. The moral and financial stakes climb as the plot moves toward a brutal turn of events.

Tragically, Joey dies after setting fire to the tenement, a blow that ripples through everyone involved. In the wake of his death, Sam Moon tells Cortlant that he will marry Mary to shield her from scandal, a revelation that clears a path for Cortlant to push forward with his redevelopment plan. The result is a complex tapestry of ambition, tragedy, and social reform that frames the uneasy balance between humanitarian aims and personal interests.

Last updated: February 24, 2026 at 09:27

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Plot questions answered

One Third of a Nation Plot Explained: Your Questions Answered

The questions people ask most about One Third of a Nation (1939): what happens in the confusing scenes, why the characters do what they do, the twists, hidden details and what the ending means. Each answer contains spoilers.

Q1

Why is the tenement exempt from modern building safety codes?

The district attorney explains that the building's age makes it exempt from current safety codes. Since no tenants had previously lodged complaints about the fire escape or living conditions, the DA cannot establish a clear crime, leaving the building's negligent ownership technically unpunishable under the law.

Foreshadowing: The exemption is introduced early during the DA's investigation, highlighting the legal loopholes that allow unsafe housing to persist.

  • building codes
  • tenement
  • exemption
  • law
  • negligence
Q2

Why does Mary take Joey out of the hospital?

After learning that Peter Cortlant owns the tenement where the fire occurred, Mary becomes frustrated with the situation and removes Joey from the hospital. This decision later contributes to Joey's deteriorating mental state, as he is left without proper medical care during his recovery.

Foreshadowing: Mary's discovery of Cortlant's ownership creates immediate tension and drives her subsequent actions.

  • Mary Rogers
  • hospital
  • Joey
  • Cortlant
Q3

What causes Joey's mental breakdown and delusions?

After being crippled by his injuries from the collapsed fire escape and being removed from the hospital by Mary, Joey develops severe delusions. He believes the building itself is speaking to him and vows revenge on the tenement, combining physical trauma with psychological distress.

Foreshadowing: Joey's delusions stem directly from his injury and removal from proper medical care, setting the stage for his tragic actions.

  • Joey Rogers
  • delusions
  • injury
  • tenement
  • revenge
Q4

Why does Joey set fire to the tenement?

Driven by his delusions and vow of revenge against the building that crippled him, Joey sets fire to the tenement. Tragically, he dies as a result of the fire he started, making his death a direct consequence of both his physical injuries and psychological state.

Foreshadowing: Joey's earlier vow of revenge against the tenement foreshadows this destructive act.

  • Joey
  • fire
  • tenement
  • death
  • revenge
Q5

What is Ethel's motive for blackmailing Cortlant?

Ethel Cortlant attempts to blackmail her brother Peter to stop the public housing project. She threatens to reveal an alleged affair between Peter and Mary to the press, using scandal as a weapon to derail the redevelopment plan and protect her own interests.

Foreshadowing: Ethel's opposition to the project becomes clear when she resorts to blackmail, revealing personal stakes beyond financial concerns.

  • Ethel Cortlant
  • blackmail
  • affair
  • press
Q6

Why does Sam agree to marry Mary?

After Joey's death, Sam tells Cortlant he will marry Mary to shield her from scandal. With rumors of an affair between Mary and Cortlant threatening to surface, Sam's marriage proposal removes a potential obstacle to the redevelopment plan by preempting the scandal.

Foreshadowing: Sam's earlier warning to Cortlant to stay away from Mary foreshadows his protective role.

  • Sam Moon
  • Mary Rogers
  • marriage
  • scandal
Q7

What motivates Mary to push for public housing conversion?

Mary persuades Cortlant to convert his decrepit tenements into public housing after learning he owns the building where Joey was injured. Her motivation combines personal anger over the negligence that harmed her brother with a broader desire to improve housing conditions for the city's poor.

Foreshadowing: The fire and Joey's injury directly trigger Mary's advocacy for reform.

  • Mary Rogers
  • public housing
  • Cortlant
  • reform
Q8

Why does Cortlant agree to rebuild the tenements?

Cortlant agrees to convert his properties into public housing after Mary persuades him of the social necessity. Though cost concerns weigh heavily, the combination of Mary's advocacy, the tragedy of Joey's death, and the clearing of scandal obstacles through Sam's marriage ultimately allows the project to move forward.

Foreshadowing: Cortlant's initial cost concerns are introduced early, creating tension that resolves only after personal and social pressures align.

  • Peter Cortlant
  • tenement
  • redevelopment
  • public housing
Q9

Why can't the district attorney prosecute Cortlant for the fire?

The DA investigates the fire but cannot establish a crime because the tenement's age exempts it from modern building safety codes. Additionally, no tenants had previously complained about the building's condition, creating a legal barrier to holding Cortlant accountable for negligence.

Foreshadowing: The DA's explanation early in the film establishes the systemic failures that enable the tragedy.

  • district attorney
  • prosecution
  • negligence
  • building codes
Q10

How does Joey's death lead to the redevelopment plan?

Joey's death after setting the fire becomes a catalyst for change. His tragic end, combined with Sam's decision to marry Mary to avert scandal, clears the path for Cortlant to proceed with the public housing plan. Joey's death transforms personal loss into a impetus for urban reform.

Foreshadowing: Joey's earlier vow of revenge and subsequent death directly tie his personal tragedy to the broader social reform.

  • Joey death
  • redevelopment
  • catalyst
  • reform

Movie threads

More Movies Like One Third of a Nation, by Mood & Story

Curated lists built around what makes One Third of a Nation tick: the same mood, the same kind of story or the same emotional payoff. Each list explains why these movies belong together.

Urban realism and social conscience dramas like One Third of a Nation

Gritty stories exposing systemic inequality through personal tragedy. Discover powerful movies that share One Third of a Nation's commitment to social commentary through realistic urban settings and emotional storytelling about class inequality and systemic injustice.

  • socially conscious
  • gritty
  • emotionally charged
  • tragic
  • determined
  • realistic
  • Tone: dark, socially conscious
  • Pacing: steady, methodical
Why these movies?

The story pattern: These films typically follow characters grappling with societal inequities, often featuring personal losses that galvanize action or reflection on systemic problems, unfolding in gritty urban environments where poverty and corruption are central conflicts.

Why they belong together: They share a commitment to social commentary through emotional storytelling, using personal tragedies to illuminate broader societal issues with unflinching realism and moral seriousness.

Bittersweet reform stories after tragedy like One Third of a Nation

Personal loss sparks determined efforts for social change. Find movies similar to One Third of a Nation where personal tragedies motivate characters to fight for social change, blending heavy emotional impact with determined optimism.

  • tragic
  • determined
  • socially conscious
  • emotionally charged
  • bittersweet
  • reform
  • Tone: bittersweet, determined
  • Pacing: steady, purposeful
Why these movies?

The story pattern: These narratives follow characters who experience profound personal losses that transform into motivation for social or political action, creating stories that balance grief with determination and bittersweet progress.

Why they belong together: They share the pattern of tragedy serving as catalyst for reform, mixing heavy emotional impact with themes of perseverance and the complex reality that meaningful change often comes at great personal cost.

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Every angle

One Third of a Nation (1939) Explained: Plot, Timeline & Characters

Everything about One Third of a Nation in one place: what happens in the plot summary, the timeline in chronological order, the characters and meaning and a spoiler-free summary. What's After the Movie adds the cast, box office and post-credit scenes.

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