Protesting innocence (of course), 21-year-old Anne Carson, convicted as an accomplice to a bank robbery, finds herself in prison with 3 equally glamorous cellmates in form-fitting uniforms: tough Jenny, unbalanced Dorothy, and deceptive, sweet-talking Melanee who (it's implied) makes unwanted lesbian advances toward Anne. The prison chaplain takes an interest in her case...or is it in her? As Anne meets the darker side of prison life, she learns that her greatest danger is the existence, somewhere out there, of unrecovered bank loot everyone thinks she hid.

After being convicted of bank robbery, Anne Carson is sentenced to a women's prison. Anne's cellmates are hardened prisoners Jenny, Melanee and Dorothy, a mentally delusional woman, who thinks Anne is "Lois," a woman who stole her husband. Anne follows prison matron Mrs. Jamieson's advice not to reveal anything about herself, prompting insults from Jenny. Anne also rebuffs Melanee, who warns her of the need for friends in prison. When sympathetic prison chaplain Reverend Fulton reads newspaper accounts of Anne's trial, he discovers that police were never able to recover the $38,000 stolen in the robbery. Feeling that the state never proved their case, he determines to help Anne. When he speaks to Anne that night, she asks him not to get involved, but expresses fear that she will soon become like the other inmates. Sometime later, Paul Anderson, who planned the robbery, but whom Anne never implicated, goes to Anne's father, Pop Carson, at his ramshackle house outside Bakersfield. Calling himself a "treasure hunter" Paul offers Pop, who sits in a wheelchair and feigns a heart condition, half of the $38,000. When Pop says that if Anne had the money, she never would have left him to care for himself, Paul threatens to reveal to the police that, years before, Pop had escaped from a Michigan prison. Although Pop still refuses to believe that Anne would lie, he agrees to let Paul look for the loot. Soon word of the robbery is common knowledge in the prison, and while Anne is with Fulton, Jenny, who is ingratiating herself with Anne, tells Melanee that she has friends on the outside who will try to find out what happened to the money. Fulton, meanwhile, tells Anne that the missing money is a problem in reopening her case, but Anne, who fled the getaway car after another robber was killed in a shootout, again insists that she knows nothing. One day, Jenny receives a note from the outside and reveals to Melanee that no one knows where the money is. A few minutes later, Melanee makes insulting remarks to Anne about her "shiftless" father, prompting Anne to attack her. Although Melanee is not hurt, Anne is given five days in solitary confinement. When she returns to her cell, Jenny comforts her. Meanwhile, at Pop's house, Paul, who is frustrated over not finding the money, orders Pop to visit Anne and demand to know were it is hidden. Anne is happy to see Pop but repeatedly says she does not have the money, even though Pop tells her about Paul and warns her that he has threatened to kill him. He also lies that he is desperate because the county has taken him off the relief rolls. That night, Dorothy's obsession that Anne is "Lois," which is encouraged by Melanee, leads her to attack Anne with Jenny's contraband knife. Jenny and a matron save Anne, after which Jenny lashes out at Melanee and promises to make her pay. Grateful to Jenny, Anne tells her that she is the only real friend she has and asks her to smuggle a note to her father. The next day, Fulton tells Anne that a friend is working on her appeal, but she says she just wants to serve her time. Fulton is disappointed in Anne, but when she mentions that Pop has been taken off relief, he promises to look into the matter. Later, Mrs. Jamieson relates to Fulton that word is out among the inmates that Anne does not have the money but that a prison break is in the works and Anne may be dragged along. Believing now that Anne is innocent, Mrs. Jamieson is arranging to have Anne transferred to a work farm. Out in the prison yard, inmates Meg and Phyllis, who are soon to be released and have tried to pressure Anne to reveal the location of the money, ask fellow prisoner Grandma Edwards to tell Anne to come to the storage room for a letter. When Anne goes for the letter, Meg and Phyllis threaten her with pipes until Jenny, who has been tipped off by Grandma, arrives to intervene. In Bakersfield, when Pop receives a note from Anne containing no mention of the money, Paul becomes furious and reveals the entire robbery plan to Pop, telling him that Anne was involved from the beginning and that he is the missing man. After searching the property again, Paul finds the empty briefcase that contained the robbery money and is even more determined to find the cash. That same day, Fulton comes to see Pop and reveals that he has investigated his case and discovered that Pop lied about being taken off relief and that he is perfectly healthy. Before leaving, Fulton sees Paul's coat and the dusty briefcase, but says nothing. When he returns to the prison, Fulton tells Anne the truth about Pop, then mentions the briefcase and suggests that she does have the money. When Anne cries and describes her impoverished childhood, Fulton gently says that she has a conscience and he knows she will give back the money. The next day, after Jenny secretly obtains a gun from the outside, a powerful earthquake hits. Large sections of the prison are destroyed, and in the mayhem, Jenny and Melanee take Anne with them as they escape. Because both Jenny and Anne are suspicious of Melanee, that night Jenny steals a truck and arranges for Anne to meet her while Melanee is sleeping. As the two women drive away, Melanee is awakened and runs after the truck. She grabs onto the back but falls off, and Jenny keeps driving, over Anne's protests. In the morning, when they reach Pop's house, Anne thanks Jenny and goes inside, not knowing that Jenny has not driven off but is watching from a short distance away. Inside the house, Paul draws a gun on Anne and Pop, but Anne refuses to reveal the whereabouts of the money. When Fulton comes to the door, Paul hides in another room while Anne coldly tells Fulton to go away. Disappointed, Fulton starts to leave, telling Anne that he has to contact the police, but just then Jenny arrives and draws a gun, threatening to kill Pop if Anne does not give her the money. Anne then leads Jenny to the money, which she hid inside a broken fence post. After obtaining the cash, Jenny forces Anne to walk with her to the truck. As Pop tells Fulton that Anne had intended to turn in the money to the police, but could not say anything because Paul had a gun on them, Paul, who has observed everything, shoots Jenny. After a second shot fells Jenny, Fulton goes after Paul, and the two men get into a fistfight. Anne rushes to Jenny just as Fulton knocks Paul out and the police arrive. Jenny dies in Anne's arms after confessing that she killed "the stoolie" who was murdered before the earthquake. After Anne tells Pop that she must go back, and says that he can take care of himself, she rides off in the police car, smiling at Fulton.