The screenplay by Nunnally Johnson focuses on a Chicago showgirl who confesses to a murder in hopes the publicity will help her faltering show business career. In the original play, and its other adaptations, Roxie was guilty but was acquitted. However, in order to conform to the Motion Picture Production Code, which regulated moral guidelines for Hollywood films at the time, this adaptation portrays Roxie as innocent but misguided in her attempt to achieve fame.[2]
Stuart Chapman starts a new job as a newspaper reporter in Chicago, and is pulled into a murder investigation together with his new colleague, veteran reporter Homer Howard. As they sit in a bar having a drink after a long day, Homer starts telling about a case he reported on in 1927 - a murder case involving the young dancer Roxie Hart.
Back in 1927, a theatre booking agent, Fred Casely, has been murdered, and his body found in Roxie Hart's apartment. Roxie's husband Amos is questioned by the police. Reporter Jake Callahan and Casely's partner E. Clay Benham reason with Roxie about what to do. They persuade her to let herself get arrested for the murder, even though she knows her husband is guilty, because a woman hardly ever gets convicted of murder in Chicago. Also, the fame she would earn for taking the blame might improve her fading career.
In jail, Roxie talks to reporters about the case, including Homer, who was just starting out as a journalist. Her husband also gets her the best lawyer money can buy, Billy Flynn, known for making a big show in the courtroom.
Billy decides they will use the fact that Roxie is a weak woman and claim she killed the man in self-defense. Billy sets up a series of interviews with journalist reporters. Roxie is instructed to charm the reporters and perform her trademark dance, "The Black Hula."
Homer is one of the reporters charmed by Roxie. He also finds out from her apartment building janitor, Michael Finnegan, that Amos is the real killer. Homer decides to help Roxie. When the press turns to report on another "lady criminal", Gertie Baxter, and publicity turns in favor of a tougher treatment of women criminals, Roxie pretends to be pregnant to sway public opinion back to her side.
To buy time to create sympathy for Roxie, Billy moves her trial further into the future. He gets Amos to divorce her. Roxie still doesn't trust the legal system completely, and asks Billy to find Finnegan and get him to testify in court on her behalf. It turns out Finnegan is dead, and the written statement he left before he died is judged as inadmissible evidence.
Roxie's fainting in front of the jury helps her case tremendously. She is found not guilty of the murder, but Amos is arrested instead, stealing the publicity from Roxie. Out of the limelight, Roxie has to choose between marrying the poor reporter Homer or a rich member of the jury, stockbroker O'Malley.
In present time, 1942, Homer finishes his story and gets up. He speaks to the bartender, who turns out to be O'Malley, the former stockbroker, who lost everything in the 1929 stock market crash. A moment later, Homer is picked up from the bar by his wife, Roxie, who arrives with their six children and announces she is pregnant with another.[3]
