A small northern town soon finds out that a large United States Army base is being established for the build-up to the Normandy landings. Soon thousands of rambunctious G.I. (military), or "Yankee" as they are known to the British, descend upon the area. On leave in the town, Technical sergeant Matt Dyson, encounters Jean Moreton while out to the Movie theater. She is the fiancée of Ken, a British soldier fighting overseas, and initially rebuffs Matt's advances. He is quite persistent, and she, doubtful about her relationship with Ken, eventually accepts him. The handsome, brash American is in stark contrast to the restrained Englishmen she has known. Soon, she is keeping company with Matt, though it is largely Platonic love at first.