A British family struggles to survive the first days of World War II.

In early summer 1939, middle-class English housewife Kay Miniver happily returns from a London shopping trip to Belham, the Thames Valley village in which she lives, and is flattered that station master Ballard has named his newly propagated rose after her. That night, Kay feels slightly guilty over buying an expensive hat, while her architect-husband Clem feels the same way about his new sportscar. When they eventually confess their respective purchases, they laugh, happy in the knowledge that they can now afford some of life's little luxuries. The next day, Kay and Clem welcome home their eldest child Vin, who has returned home for the summer holiday and is a bit pompous after his year at Oxford. Vin embarrasses his parents when he insults Carol Beldon, granddaughter of local aristocrat Lady Beldon, when Carol comes to ask Kay to influence Ballard to withdraw his rose from competing against Lady Beldon's in the annual flower show. At a dance that night, Carol receives a secret message from Vin asking her to meet him. The two confess their mutual attraction and promise to write to each other while Carol and her grandmother are away in Scotland. Some weeks later, concern over the fall of Poland dominates village conversations, and at church on Sunday, the vicar's sermon is interrupted by news that England is now at war with Germany. While Clem, Kay and their two youngest children, Toby and Judy, return home, Vin goes to the Beldon estate to make certain that the newly returned Carol and her grandmother are adequately prepared. Although Lady Beldon at first refuses to take seriously new air raid regulations, Vin takes charge of the situation. He and Carol also come to an "agreement" about their relationship and kiss for the first time. Eight months later, after Vin has left school to join the RAF, the Minivers, like others in the village, have made accommodations for the war, but have yet to seriously feel its effects. In the pub, the locals laugh at the radio admonitions of the traitor Lord Haw Haw that England will soon fall, and discuss a German pilot who parachuted out of his plane and may be hiding near the village. That night, Vin proposes to Carol, much to the delight of Clem and Kay. Immediately thereafter, Vin is ordered back to his airbase, and in the middle of the night, Clem, a member of the Thames River patrol, is awakened and told to meet at the pub. Like the other local boat-owners, Clem is at first amused and somewhat irritated by the call-up, but soon finds that his is one of thousands of privately owned, seaworthy crafts needed to evacuate stranded British soldiers from Dunkerque, France. Five days later, Kay's only news of what Vin and Clem may be doing comes from the papers. When she goes for a stroll in her garden one morning, she sees the boots of the missing German pilot. Unable to get the sleeping flyer's gun away, she rushes to the house, but he forces his way into her kitchen and holds her at gunpoint while she brings him food. Weakened from his wounds, the flyer collapses and Kay is able to take his revolver and call for help. Before the police arrive, though, the German bitterly tells Kay that England will soon fall, just as Holland and Poland did, and she slaps him. After the police take the flyer away, Clem returns in his badly damaged boat, unharmed, but exhausted from his ordeal, and soon they learn that Vin, too, is safe. A short time later, Vin and Carol marry, after Kay convinces Lady Beldon that the couple are right for each other. One night, while Carol and Vin are on their honeymoon, Clem, Kay, Judy and Toby retreat to their bomb shelter while an air battle rages overhead. As the children sleep, Kay calmly knits and Clem reads until the bombing becomes so fierce that the children awaken, crying, and the family fearfully huddles together, realizing that their house has been hit. When Carol and Vin return from their honeymoon, they are shocked by the bomb damage, but Kay and Clem shrug off the partial destruction of their home and look forward to going to the annual flower show. At the show, Lady Beldon is secretly informed that she has won the competition, but when Kay helps her to realize that the judges chose her rose over Ballard's more worthy flower because of her position in the village, Lady Beldon announces that Ballard has won the prize. The show is then interrupted by an air raid warning. As Kay drives Carol home, they are heartsick at the destruction they see. When a plane dives toward them, Kay thinks that the car has been hit but soon realizes that Carol has been badly wounded. Kay is able to get Carol home, but she dies before medical help can arrive. On Sunday morning, in the badly damaged village church, the vicar sadly talks of those who have died, including Carol and Ballard. As the vicar reads from the Ninety-First Psalm, Vin goes to Lady Beldon's pew to comfort her, and more British planes take to the air.