It stars Margaret Sullavan, Ann Sothern and Joan Blondell, and features Fay Bainter, Marsha Hunt, Ella Raines, Frances Gifford, Diana Lewis, Heather Angel, Dorothy Morris and Connie Gilchrist.

It is set in a field hospital during the Battle of Bataan (January–April 9, 1942) against the inexorable advance of Japanese forces down the peninsula during the early months of the United States' involvement in World War II.

Alice Marsh talk about their desperate need for supplies, especially quinine: Men are surviving surgery only to die of malaria.

Marsh also tells a resistant Smith that there is only one chance for her—she must join the evacuees bound for Corregidor, and thence to Australia, where new medicines may save her.

Nurse Flo Norris returns from Mariveles with what supplies she could find; 9 women civilian refugees from various backgrounds are pushing the truck.

They lack experience and training and at first find it difficult to adjust to all the horrors of their work and living in close quarters under constant fire.

The jealousy between the two women is made worse by the fact that Smitty must constantly reprimand Pat for ignoring regulations and doing dangerous things such as lighting cigarettes outside at night.

A soldier dies in Connie's arms with the words “I'm all right.” On their first day, just before an air-raid, one of the volunteers, Sue West, steps outside and disappears.

Grace's leg is wounded, and she loses her temper with Smitty, throwing Pat's relationship with Holt in her face.

Dispirited, the women feel they cannot win, but Pat declares “We can't lose!” Using a map she got from Holt, she describes to the nurses—and to the wartime audience—how resistance has thwarted Japanese plans for easy conquest.

Cast notes: The film is based on a play by Allan R. Kenward which opened in Hollywood, California in September 1942.

The play was also presented on Broadway, under the title Proof Thro' the Night with Carol Channing, Florence Rice and Ann Shoemaker.

Allan R. Kenward's play opened in a small Hollywood theatre in September 1942 under the title Cry 'Havoc', and two weeks later, in October 1942, MGM bought the rights to it for #20,000.

The waiver was granted due to the subject's timeliness, and the show opened on Broadway on December 25, 1942 under the title Proof Thro' the Night.

Actresses considered for various roles between December 1942 and May 1943 include June Allyson, Eve Arden, Mary Elliott, Bonita Granville, Laura La Plante, Diana Lynn, Marilyn Maxwell, Kay Medford, June Millarde, Susan Peters, Frances Rafferty, Donna Reed, Helene Reynolds, Ann Sheridan, Mary Treen, Lana Turner, Elena Verdugo, and Tsing, a Chinese ingenue.

[3] Leonard Maltin also noted that its stage origins were obvious, but that it offered a "pretty honest picture of war".