Each of the Mulligan sisters Bridget, Margaret, Colleen and Molly strives to find her place in the rapidly changing world in these early days of World War II. With their father ailing, Margaret takes over management of the family's grocery store trying to keep hoarders at bay while daydreaming of a June wedding. Meanwhile Bridget focuses on her board exams and hopes to be accepted as an Army nurse. Beautiful Colleen, the "family flibbertigibbet" just wants to have fun despite the dire news of the war. But it's the "baby" fifteen-year-old Molly who seems to be the glue that holds the family together.
With siblings, friends, and beaus being shipped out weekly, the remaining Mulligans quickly realize that this war will be fought on two fronts at home and overseas.
Each of the strong, hopeful Mulligan sisters will do their part if they hope to see victory and the end of the war.