Cynical socialite Pamela Starr goes out with Captain Tedford to celebrate a British naval victory, but when Tedford takes liberties after seeing her home, she pushes him away, causing him to crash through the bannister at the top of the stairs and fall to his death. Pamela is tried for manslaughter but is acquitted after her mother, Miss O'Neil, comes to England and instructs Pamela's lawyer, Gordon, to enlist Pamela in the auxillary nursing service unit bound for the front lines in France. Pamela resents the trick but begins training as a nurse. She is unaware of her mother's involvement or that her mother, whom she has not seen since she was an infant, is O'Neil, the head matron of the unit. The other girls in the unit, Gail Halliday, Ginger, Millie and Phyllis, are suspicious of Pamela because of the trial and her haughty attitude, and matters grow worse when Pamela is locked in a stateroom with Gail's fiancé, Lieutenant Larry Hall, while their ship to France is being bombed. Soon after they arrive in France, Pamela and Larry meet again during an air raid. Gail's suspicions and accusations intensify despite Pamela's assurances, and so Pamela vows that she will steal Larry. O'Neil tries to dissuade Pamela, but when she refuses to listen, O'Neil assigns her extra duties to toughen her, and time passes as Pamela works hard on her job and on Larry. One night, Larry tells her that he loves her and wishes to break his engagement to Gail. Pamela replies that their relationship is only a flirtation, but Larry insists that she accept his RAF wings as he is going on a dangerous patrol the next morning. Larry is shot down during his patrol and is taken to Pamela's hospital, where he recovers quickly and again asks for Pamela's love when she says goodbye before the unit is sent on a mission to the front. Ginger overhears Pamela tell Larry that they are through and that he must return to Gail. Gail, however, misunderstands when she discovers that Pamela was with Larry, and later, when Gail, Pamela and Ginger are in a truck enroute to the front, Gail lets Ginger out, then deliberately drives to a village under barrage. Ginger finds O'Neil and Frances, another matron, and they go to the village, where Pamela has dragged Gail to shelter in a basement. Pamela lies to protect Gail, and after O'Neil saves her from being crushed by a falling beam, Pamela admits she has behaved awfully to them all. The barrage increases, and Ginger tells Gail that Pamela was not trying to take Larry away from her. Gail runs outside, intent on getting through to their side and telling them to end the barrage, but she is hit. O'Neil stops Pamela from pursuing Gail, after which O'Neil goes to Gail's body, then crosses through the front. While they wait in the basement, Frances tells Pamela that O'Neil is her mother. O'Neil is successful and the barrage ends. Soon after, Pamela visits O'Neil in the hospital, where the mother and daughter are reconciled, and Pamela announces that she will tell Larry that she loves him.