Based on an actual 1924 case of future US Attorney General Homer Cummings, a prosecutor goes against politicians, witnesses, and public opinion to prove that the man they want convicted is innocent.
On the street the priest Lambert is shot in the head. Lambert before had told his assistant that he must go to a sanatorium. Police investigate the murder, and prosecutor Henry Harvey (Dana Andrews) pressures Robbie (Lee J. Cobb) to find the murderer. Dave Woods (Same Levene) writes news articles about the inept police. Mayor McCreery (Robert Keith) and Commissioner Paul Harris (Ed Begley) call on Harvey at home and demand results. Harvey tells Robbie, who orders Lt. White (Karl Malden) to circulate composite drawings to find suspects. Woods learns from Desk Sergeant Dugan that they arrested a man in Cleveland who was identified.
White and Robbie interrogate John Waldron (Arthur Kennedy), who asks for a lawyer. Irene Nelson (Cara Williams) comes in and says Waldron was there and said he was leaving town. Harvey learns the lab found that the bullet came from Waldron's gun. After several hours the exhausted Waldron signs a typed statement and then falls asleep.
Several witnesses tell a proceeding what they saw. Waldron tries to deny the statement. In his cell Waldron tells Harvey that he didn't do it. He says he brushed off Irene, and she is getting back at him. At a golf course an influential man tells the public defender to emphasize Waldron's war record. McCreery tells Harvey that he can be governor.
Harvey prosecutes the case and explains the evidence, but he has concluded that Waldron is innocent. Afterward the judge threatens to prosecute Harvey. Robbie tells angry men outside the police station to go home. McCreery tells Harvey that he is fighting the whole town. Harvey's wife Madge (Jane Wyatt) comforts him at home. Harris tells Harvey to indict Waldron and says he owns the realty company. He says they have to win the election and pulls a gun. Harris says that Madge gave him money for the land deal.
In court Harvey questions a man who said the gun glittered, but Harvey explains a black gun could not have glittered in the dark. Harvey challenges the witnesses and reports that in his seven re-enactments with his men none of them could properly identify the man. He says that Irene applied for some of the reward money. Woods passes a note to Harris about getting into the land deal. Harvey explains that five ballistic experts found that Waldron's gun could not have fired the bullet, and he dramatically demonstrates why. Harris shoots himself while the court is in session. Afterward Harvey asks Waldron what he is going to do now.
This conscientious prosecuting attorney is guided by
the legal code of ethics that the prosecutor's job is not to gain
convictions but to see that justice is done. This true story dramatizes
the importance of withstanding political and public pressures
to convict someone lest an innocent person be punished.