During one of her famous parties, Washington socialite Jo McBain, the daughter of Senator Tom Reynolds, learns that her boyfriend, Lt. Col. Schuyler "Sky" Fairchild, is being transferred to Paris to participate in SHAPE. As soon as she learns that Sky will be accompanied by the flirtatious Phyllis Turnbull, Jo announces that she is going to Paris, too. The party ends abruptly when Jo's ex-husband Andrew, who has snuck back to his former residence to retrieve his dog Angus and books he needs for his scientific Army research, gets into a loud argument with Jo. Andrew, who fell in love with Jo during a South Sea island vacation, now reviles her manic socializing, while Jo disdains his boring work and friends. Later, Jo's father, who has a soft spot for Andrew, convinces Jo join the WACs so that she can be sent to Paris and protect her interests with Sky. Assured by Tom that he will use his influence to secure a commission for her, Jo enlists and is assigned to Company B at the Fort Lee, Virginia, training camp. Jo immediately antagonizes her sergeant, Toni Wayne, with her flippant snobbishness and disregard for rules. Fellow recruit Clara Schneiderman, a former showgirl known as Danger O'Dowd, however, is impressed by Jo's sophistication and befriends her. During their initial interviews, the dimwitted Clara, who joined up to escape her wolfish admirers, declares that she wants to work in intelligence, while Jo repeatedly demands her commission. After a series of phone calls, including one to Gen. Omar N. Bradley, Jo learns that her father has pulled no strings on her behalf. Despite being a lowly private, Jo refuses to take her training seriously and makes it clear that she is just marking time. Meanwhile, at a nearby Army camp, Andrew instructs Sgt. Norbert "Noisy" Jackson to procure four women on whom to test a new cold weather fabric he has developed. Upon observing the women at the camp swimming pool, the womanizing Noisy picks buxom Clara, whom he recognizes as Danger O'Dowd. Andrew then shows up and is startled to see Jo among the recruits. After overhearing her on the phone arranging to meet Sky during her upcoming pass, Andrew insists that she be included in the study. For the experiment, Andrew has the women perform various tasks in simulated blizzard conditions and is particularly harsh on Jo. When Sky arrives for Jo, Andrew prolongs her assignment until it is too late for her to use her pass. While driving Jo back to Fort Lee, Sky tells her that she can earn a commission if she can impress her commanding officers for the next three weeks. To Andrew's surprise, the newly motivated Jo volunteers for the optional firing range instruction and impresses him with her efforts. Later, Jo is about to go out with Sky, when Clara, who has been dating Noisy, reveals that she told Noisy about Jo's plans. As feared, Andrew appears before Jo can leave and announces he is conducting another test. Andrew then forces Jo to endure hours of traipsing through rain and mud while dressed in his experimental wet-weather gear. Fed up, Jo starts to yell at Andrew and finally slaps him. Soon after, Jo's superiors conduct a hearing to determine whether she should remain in the WACS. Although Andrew defends her, Jo admits that she is no soldier and should leave. That night, during a party celebrating Company B's victory in a marching competition, Clara tricks Noisy into proposing to her. At the same time, Jo and Andrew, who has accepted a post in Korea, agree to a friendly truce, having acquired a new respect for each other. Jo makes plans to elope with Sky as soon as she is relieved of duty, but as Sky is driving her out of the camp, she starts to have second thoughts. Then, when a truck of fresh recruits passes them on the road, Jo jumps out of Sky's car and runs to catch up with the truck. After jumping aboard, Jo tells the unsuspecting women that she is planning to go to Korea.