Torrential rains cause flooding which threatens to overwhelm the state prison, and the inmates are further endangered when a typhoid epidemic breaks out. Three local nurses--Judy Grayson, Pepper Clancy and Patsy Sutherland--rush to aid the prison doctor, Dr. Hartman, but he too, is felled by typhoid. Dr. Hartman had previously requested the aid of Stephen Dale, a doctor imprisoned for a mercy killing, but Dale, bitter over society's treatment of him, refused. Dale's instincts as a doctor prevail, however, when Mousie, one of tough inmate Frank Gaffney's stooges, is wounded in an escape attempt instigated by Gaffney. Dale tends to Mousie while Mousie warns the warden that Gaffney has a store of dynamite. Once he is in the prison hospital, Dale is pressed into helping the nurses care for the sick and inoculate the healthy. Gaffney is put into solitary confinement, where he and his pal Jackpot Dugan, an inmate helper at the hospital, trick Dale into believing that Gaffney has typhoid. Later that night, Dale confesses to Judy that he has a renewed desire to live and to contribute to humanity's well-being. He intends to ask for parole in the morning, but his plans are torn asunder when Gaffney, Jackpot and their compatriot Tony Miller begin their escape attempt. Gaffney kills a guard and forces Dr. Hartman to reveal the prison gate's combination. He threatens to injure Judy if Dale does not accompany them, and so Dale opens the gate. Gaffney and his men escape in an ambulance, with Dale tied up in the back. Once they are on the road, Gaffney reveals to Dale that he kidnapped him so that Dale can surgically alter Gaffney's face. The highway patrol spots the stolen ambulance and gives chase, during which Dale fights with his captors and succeeds in throwing Miller out of the moving vehicle. The ambulance then crashes, and Gaffney is seriously wounded. While Dale tries to save Gaffney's life, Gaffney orders Jackpot to tell the police that Dale was kidnapped and was not a willing participant in the escape. Gaffney tells Dale about a hiding place he can use, after which he dies and Dale is forced to flee from the police, thinking that they believe she was a party to the escape. Meanwhile, Jackpot has been shot and killed by the police before he can carry out Gaffney's order, and the search for Dale begins. Judy, who has confessed to Pepper that she is in love with Dale, is tricked by District Attorney Parker into leading his men to Dale after she finds out from Mousie where he is hiding. Dale, who returns Judy's tender feelings, does not blame her for his capture, and stoically accepts his fate when he is returned to prison. The three nurses are leaving the prison when Pepper remembers Jackpot telling her about the diary he kept. The trio find the diary, and its entry discussing Gaffney's plans completely clears Dale. The warden assures Dale that he will be fully pardoned, and Dale and Judy celebrate with a kiss.