A law professor on sabbatical investigates organized crime with the aid of his former students.
John Lindsay (Edward G. Robinson) is giving his last lecture in law school before his sabbatical year. He says goodbye to his students and the former students who have become his friends. He invites Paul Ferguson (John Beal) to come home with him; but he says no because Lindsay’s wife is getting ready for their trip to Europe.
At home Jerry Lindsay (Barbara O’Neil) is packing and does not want to stay in town with John. She knows he would keep working. She tells him to go out to a movie, and he leaves.
At a theater John finds people fleeing from a stench bomb. Lindsay takes the theater manager to meet his brother-in-law Tom Ross (Arthur Loft), a reporter. Lindsay tries to explain about two gangs of racketeers fighting over turf. The manager is afraid of dynamite bombs in his home and leaves. Lindsay urges Tom to write a story to draw attention to the problem. Tom suggests he go to the government civic committee but warns him it is a private meeting.
Lindsay listens to the meeting led by George Leander (Charles Halton) who complains about corruption and calls on the District Attorney Bert Beery (Douglas Wood). Eugene Ferguson (Otto Kruger) asks him why he has not appointed a special prosecutor. Beery says no one will take the job. Lindsay speaks up from the back, and Leander tells him it is a private meeting. Lindsay says they have the force of law and public opinion over the racketeers; but Leander brings in a policeman to make Lindsay leave. As he goes, Eugene invites him for a drink.
At a bar Eugene says Lindsay is the man they need to be the special prosecutor. Lindsay says he could postpone his trip for a few weeks, and he does not need any pay. Eugene calls Kitchell (Robert Mildernass) and tells him they have nothing to worry about.
At the pier Jerry worries as she waits for John. Paul tells her he could not find John. Tipsy John arrives late and tells her he had an adventure. He is not taking the boat because he was drafted.
Eugene tells his son Paul that he has taken a dangerous job working for Lindsay. Paul wants to help clean up the rackets. Lindsay announces to the press that they will not give tribute to criminals. People listen on the radio as gangsters pressure a man who refuses and destroy his counters. In a montage gangsters destroys the milk business.
John Lindsay calls witnesses together and tries to persuade them to testify. J. W. Butler (Louis Jean Heydt) says he has a wife and family but found he could not buy insurance if he agreed to testify. Lindsay writes down the name of the Acme Insurance Company. He offers to assign two body guards to anyone who agrees to testify, but no one volunteers despite Paul’s emotional plea.
In his office Lindsay calls in his assistant Simpson and asks him to get a complete set of a company’s books. Paul says he will show him how to get them. Secretly Simpson calls Mr. Kitchell about the books. Kitchell calls Frankie Ballou (Wendy Barrie) who informs Eugene while he is playing piano. She tells him that Lindsay wants to see her. Eugene explains that he is using Lindsay to clean up the riffraff like Cronin and other undesirables. He says it will become a recognized industry. He embraces her, and they kiss.
Two bodyguards tell Lindsay that she must have left town. Lindsay is told that Frankie is there, and she comes in. He dismisses the two men. She tells Lindsay he will not be doing this for long unless he prosecutes some of the gangsters. He asks her what she does, but she is evasive. He offers her candy, and she gives him her fingerprints. She advises him to meet these people and offers to give him a tour. He calls his wife and tells her he will not be home for dinner.
Lindsay and Frankie go to the Martin Café. He asks her who protects this place, and she says Cronin. At another table Eddie Girard (Marc Lawrence) tells Martin to sit down so he can talk to him. Lindsay gets up to call his wife. Girard tells Martin he needs protection, and he is in the wrecking business. Martin says he will not pay. Girard goes over and talks to Frankie, who asks why he is in one of Cronin’s places. He suggests they get rid of Cronin. She tells him Lindsay is going to clean up the town. Girard walks off before Lindsay comes back. Frankie gets Lindsay to dance the Big Apple with her. Jerry comes in with Paul, and she sees her husband dancing wildly with Frankie. Lindsay introduces them to Frankie. Tom Cronin comes in and goes over to Frankie, and he meets the others. Lindsay invites him to join them. Cronin says he is having trouble with hoodlums who are trying to move in on him. Frankie writes a note and asks Cronin to dance. She advises him to leave town. Cronin says he will talk to Paul. She throws the note to Girard. A shot is heard, and Cronin is murdered.
Leander complains to Lindsay about the murder under his nose. Lindsay and the D. A. say witnesses will not cooperate. Eugene defends Lindsay, who goes back to work. They leave, and Frankie comes in. Lindsay asks if she knows any of those three men, and she says no. She asks him about Eddie Girard and her note. He says Girard killed Cronin, but he can’t prove it. He asks her why he was killed. He asks who is taking over Cronin’s business. He noticed her in several clippings and that she had a byline. He mentions her interview with Eugene, and she stalks out.
In a car she tells Eugene what happened.
Jerry calls on Mrs. Butler (Fay Helm) and asks her to help her husband by persuading her husband to testify. Jerry wants Lindsay to finish his job. Mrs. Butler says her husband has gotten death threats, but so has Lindsay. Mrs. Butler has two children.
Lindsay learns that the Acme Company stock is mostly owned by Eugene. Simpson was listening on another line and leaves. Paul asks Lindsay about Acme. Lindsay has been working all night and is irritable. Jerry comes in, and John tells her Acme has been insuring plate glass that gets broken. He considers resigning. Jerry advises him to finish his job. Lindsay is concerned that Paul would be affected if Eugene was charged. Butler calls Lindsay and offers to testify, and Lindsay guarantees him protection. Lindsay sends Paul to escort Butler to his office.
Girard rings the bell and tells Butler he came to take him to Lindsay. They get in the car and drive off. Paul pulls up in a car, and Mrs. Butler tells him her husband left with a man to go to Lindsay’s office. Paul reports this to Lindsay. A phone rings, and Lindsay learns that Butler was killed and thrown from a car. Lindsay tells Paul and wonders how they could have known. Lindsay speaks to his staff and fires all of them.
Lindsay is hiring the lawyers he knows, but the D. A. tells him he no longer has any funding. Lindsay resigns. He speaks to his former students and asks for their help in his quest as a private citizen. He wants a regiment full-time without pay. They say they are practicing law, but he says they must bring law back to the city. They volunteer. Lindsay says he will raise money by borrowing from the loan sharks. He sends them out to get loans. They pack up his records first.
In Lindsay’s home Paul collects the money the men have borrowed. The D. A. has brought Inspector Gleason (Ivan Miller), who did not toe the line, to help Lindsay. Mrs. Butler comes in and tells Jerry that men are following her. Lindsay sees them and has the Inspector bring in the men while Jerry calls her brother Tom to bring over photographers. Paul and the Inspector with a gun bring in the gangsters who are searched to remove their guns and brass knuckles. Lindsay has a “before” picture taken of the three hoodlums. He says they do not have courage but come in groups with weapons. He says he will beat up one of them, and they get into a fight. Photographers take pictures. The D. A. makes a call and describes the fight. Paul and Jerry root for John who finally knocks out the man. Then Lindsay beats up the other two men. The “after” photo appears in the newspaper also.
Eugene reads the news article and is talking with Kitchell and Frankie, who asks about the Acme books. Eugene sends Girard who breaks into the Lindsay house at night. In double beds John gives orders to Jerry. He gets out of bed and lies down next to her and kisses her. She bought him a present. He opens it and finds a pistol. She explains how to take the safety off. Just then Girard points his gun at them; but Lindsay shoots the gun out of his hand, and Girard flees.
Two policemen and Lindsay arrest Girard.
Lindsay wants Tom to investigate Kitchell by putting a motion picture camera in his apartment. His men do so with a microphone too. Tom tells them to watch it 24 hours a day.
The Governor asks the D. A. to resign, but Lindsay says they know who they are and will clean them out. He asks for and gets 24 more hours. The D. A. refuses to arrest them all, but Lindsay says he will risk it. A montage shows police arresting many hoodlums. Paul sorts them out and gets a call from Kitchell who wants him to come over.
Paul goes there and finds Kitchell on the floor dead. The phone rings, and he answers it. He hears it is Eugene, who says he will take care of Lindsay tonight and that Paul will leave town. Paul hangs up and leaves.
Paul tells Lindsay that Kitchell was killed so that he would not talk to him. Paul is angry and says he will tell the world his father is the head of the crooks. Lindsay tells him not to do that yet. He tells Paul to interrogate the criminals. Tom comes in, and Lindsay tells him to run the story.
In his private office Lindsay dictates a will to Jerry. Paul comes in and says he cannot break down the witnesses. Lindsay goes out on the terrace and pleads with them to testify. He says they have the head man, and Kitchell was killed. He says they are inside, and he wants them to identify them. He says lawyers risked their lives for them. They argue; but one man volunteers, and the others follow his lead. They go in the house and begin to identify the men who smashed their windows or sold them insurance. Frankie comes in and goes into Lindsay’s private office with him. Lindsay brings in Eugene and tells him that she killed Kitchell. She says the report is he committed suicide. Lindsay shows them a film in which she is seen in Kitchell’s house. Kitchell lets in Eugene, and they argue. Eugene slaps him and stalks out. Kitchell calls Paul and is shot. Frankie drops the gun and leaves. Lindsay turns on the light and tells Frankie she will get the electric chair unless she cooperates with him. She offers to tell her story, and he promises to save her life. She asks about Eugene, and Lindsay is thinking of Paul. She goes to write her story in another room. Lindsay tells Eugene that Paul is a fine boy. He wants Paul to take his place and handle the prosecutions. His only handicap is Eugene and his money. Lindsay asks if he made out a will and tells him he made one for him. Paul gets only part of his estate, and the Butler family gets a trust fund. The rest goes to a fund for the ongoing investigation. Eugene agrees to have Lindsay as the executor. Lindsay asks him to sign it, and Eugene does so. Eugene asks Lindsay if he can borrow his car, and Lindsay gives him the keys. They say goodnight and shake hands, and Eugene leaves.
Frankie is writing her story. Outside Eugene gets into the car. A man tells Paul that a plot to kill Lindsay must be stopped. A bomb is in his car. Eugene starts the car which explodes. They hear it, and Paul tells Frankie about the bomb. Lindsay tells Paul his father was in the car. Frankie blames Lindsay, who says he knew nothing about it. Lindsay tells Paul that his father had courage but took the wrong direction. Jerry embraces Lindsay.
Lindsay with Jerry on his arm goes back to the college. He tells her they will have their honeymoon on his next sabbatical. He kisses her and goes up the steps.
This drama was believed to have been based loosely on the law career of Thomas Dewey who later became governor of New York. The story shows how conscientious lawyers can help to bring criminals to justice so that people can be protected from violence and extortion. Unfortunately the scene where Lindsay beats up three hoodlums deviates from the theme that might does not make right.