New Zealand was used as a hub for American Marines, waiting to be shipped out to fight in the South Pacific during WWII; and this movie tells the story of four "kiwi" sisters and their romantic entanglement with American servicemen.
Joan Fontaine plays the oldest sister (nicknamed "Iceberg Anne" by Evelyn). Anne started as the unsympathetic old maid who looked down on all local girls who threw themselves at the American soldiers, then ended up falling in love with Charles Drake's down-to-earth Captain Dick Bates.
Jean Simmons plays the second sister, Barbara, a widow who finds herself drawn to the cynical Captain Jack Harding, played by Paul Newman. Jack is in charge of investigating marriage requests submitted by marines, ensuring that the lonely boys are not infesting the USA with "undesirable" women; hence, he does not believe in having romantic relationship with any women. Barbara is in love with Jack, but does not want to see herself becoming Delia and another one of "those girls." Their feelings for each other grew strong and against their better judgments, they begin an "almost" love affair for a few months, and then Jack sets sail to join the other marines fighting in the South Pacific.
Piper Laurie plays Delia - the black sheep of the family (and the actress with the least screen time). Her endless string of love affairs with American servicemen, while her husband rots away in an POW camp, eventually leads to her own death and a scandalous murder trial. Ironically, this is also what finally brought Barbara and Jack back together.
Sandra Dee plays the baby sister, Evelyn, the only sister who ended up marrying a local boy after he returns home from war. Evelyn's role provides comic relief in this movie, being the typical 15-going-on-30 teenager and making smarty-pants comments on the ups and downs of her older sisters' love live.