In 1943, two hundred and ten U.S. soldiers report for duty at the 1st Army Ordnance Depot, near a Lancashire town in northern England. Watching the truck convoy move through the streets, the locals refer to the Americans as “Yanks.” The Moreton family, who own the general store, discuss the latest influx during breakfast. Young Geoff Moreton wants to earn money, delivering fish and chips to the army base. However, his mother, Clarrie Moreton, is more negative about the pompous Yanks, while reminding daughter Jean about her sensible British boyfriend. During their first visit to town, Matt, a U.S. Army sergeant and cook from Arizona, and his friend Danny, a prizefighter, meet a spirited bus conductress named Mollie. She invites the two Americans to the movies later and brings along her friend, Jean Moreton. While Danny and Mollie flirt and run off to be alone together, Jean is reserved and tells Matt about her future fiancé, Ken, whom she has known since childhood. Matt appears unconcerned about the competition for Jean’s affection and wants to meet her at the movies again. However, she is reluctant as her mother watches the two interact. Meanwhile, John, a captain in the U.S. Army, has been stationed at the Lancashire base for six months and has developed a friendship with a beautiful British woman named Helen, who volunteers with the Red Cross, and whose husband is currently away serving in the British Navy. John is also married, but indicates to Helen that the relationship with his wife is strained. Although he is attracted to Helen, he is cautious about making any overt sexual advances. Jean winds up joining Matt for another date at the movies, and enjoys listening to him discuss his dream of owning a motel chain in Arizona. After three weeks getting to know each other, Jean wants to introduce Matt to her family and reassures her skeptical parents that they are simply friends. Meanwhile, Helen seeks John’s advice about whether she should take her son, Tim, out of boarding school where he is miserable. John reminds Helen that she must forget tradition sometimes, and kisses her before returning to base that night. On Sunday, Matt arrives for afternoon tea at the Moreton residence and brings a decorated cake he made. Clarrie Moreton thanks the young serviceman, but puts the cake away for later, stating that they already have too much food. Matt invites Jean to the base to watch Danny’s boxing match and kisses her, but when Ken arrives back in Lancashire for a two-week leave, he and Jean become officially engaged. As the Moretons toast the young couple, Matt is despondent and gets drunk with Danny at a pub. He initiates a fight with a British soldier and is reprimanded on base. After Ken returns to the battlefront, Matt and Jean continue to see each other and attend a New Year’s Eve party, along with Danny and Mollie. During the festivities, a brutish U.S. soldier and his friends viciously beat up an African-American GI for dancing with a white girl. When Matt and Danny indicate that the black man was courting trouble, Jean and Mollie refuse to tolerate their prejudice and invite the other black GIs to dance with them. Matt pulls Jean off the dance floor and takes her to a hotel for a nightcap. Although they argue about the incident and admit they have different values, Jean still wants to continue their romance. One day, John arrives at Helen’s house to take her on a spontaneous trip to Ireland to collect alcohol and other luxury goods at a military exchange. Helen loves the adventure and passionately kisses John on the plane ride. Returning to Lancashire, the two make love for the first time. Meanwhile, a golf course is plowed to make way for another U.S. Army camp, where the American troops practice for an invasion of Europe. At the Moretons’, Jean minds the store while her ailing mother remains in bed. One day, Jean returns home from an afternoon with Matt and learns that Ken has been killed in action. Clarrie Moreton claims Ken knew about Jean’s affair and did not want to return, blaming her daughter and Matt for his death. During a trip to a seaside hotel in Wales, Helen tells John she feels guilty about their adulterous getaway. He understands and drives her back home. Meanwhile, Jean wants to get away and Matt takes her to a nice hotel out of town. As the two begin to make love, Matt suddenly stops and becomes withdrawn. On the train ride home, an uncomfortable silence exists between them. Back in Lancashire, they attend Danny and Mollie’s wedding, but Jean runs away from the celebration. Matt follows her home and says he loves her, but is “not ready” for a serious relationship and was afraid of leaving Jean pregnant in the middle of a war. She asks him to go and wishes him well. Elsewhere, John stops by Helen’s concert rehearsal and learns her husband is coming home on leave. Knowing their affair is over, the two say goodbye. The American soldiers decamp in preparation for invading northern France. Meanwhile, Clarrie Moreton passes away, and on the day of her funeral, a departing soldier gives young Geoff Moreton a handful of coins. Jean receives a homemade cake from Matt with the words, “So Long, Love You.” She rushes to the train station and fights through the crowd of women looking for their boyfriends and husbands. After encountering Mollie, who is pregnant, the two women stand on an elevated passageway and scan the faces of soldiers on the platform. They finally see Danny and Matt smiling and waving from a train window. Jean screams that she is sorry, and Matt promises he will return.