The staff of "Yank" magazine are among the first American troops into Tokyo after the Japanese surrender. Their mission: produce an issue of the magazine...in three days. To accomplish the seeming impossible, they reluctantly enlist the aid of black marketeer and arch-conniver Joe Butterfly, who sets them up in a palatial private mansion, complete with lovely daughter -- strictly against regulations. How much trouble can our heroes talk their way out of?

In Japan in Sep 1945, Yank magazine editor Sergeant Ed Kennedy and his staff, photographer Private John Woodley and correspondents Sergeant Jim McNulty, Sergeant Dick Mason and Chief Yeoman Saul Bernheim, board a transport ship to cover the surrender of the Japanese Army. Woodley, a charming troublemaker, dispatches with rival Harold Hathaway, editor of the civilian magazine Trend , by pushing him off the plane. Later, the Yank staff celebrate their imminent discharges with martinis made from Colonel E. E. Fuller's gin and prized olives, which Woodley has stolen. At the same time that they learn they will have to stay in Tokyo another three days to produce the first post-war Yank issue, Fuller discovers both the theft of his gin and the mistreatment of Hathaway, and orders that the recently demoted Woodley be discharged immediately. The four remaining staffers move on to Tokyo, where thousands of American soldiers are competing for space in the hastily erected military headquarters. The staffers' attempt to get to work is beset with problems: First, Fuller's assistant, Sergeant Oscar Hulick, forces them to set up their office in the crowded enlisted men's barracks, and soon after, Hathaway bribes them with job offers at Trend in exchange for missing their deadline, so he can be the first to publish in Japan. In addition, they meet Japanese con man Joe Butterfly, who has signed a secret contract with Hulick to sell confiscated Army supplies on the Japanese black market. The goods are locked inside Hulick's rolltop desk, so when he is suddenly ordered to move to a new office, leaving his furniture behind, Joe watches over the desk covetously. Ed commandeers it, not knowing what is inside, but Joe offers to find him a cushy office in trade for it. Joe brings the staff to the home of Mr. Sakiama in an impoverished village nearby, furtively promising the owner that the presence of the Americans will mean more food and supplies for the village. Ed moves in but remains suspicious of his hosts, especially after the young boy sings "You Are My Sunshine," the song Tokyo Rose played with torturous frequency during the war. Soon after, Hulick arrives to reclaim his desk, but after Joe deliberately calls him "partner," Ed insists that the desk be opened, and finds the goods inside. Joe offers Ed the contract to use as blackmail against Hulick, who agrees not to report the Yank 's unorthodox office space to the colonel. Ed tries to chastise Joe, but when Joe points out that "honest man watch children starve," Ed instead agrees to give the goods to the villagers. The staff faces further pressure to keep their presence a secret when another colonel, Hopper, asks to bunk with them, but McNulty lies that the area is reserved for the top-secret project of an eminent general. The next day, Joe arrives with Woodley, who has gone AWOL from the transport ship in order to help his mates finish the magazine. Their boss, Major Ferguson, visits, and Ed manages to hide Woodley and convince the kindly officer that they will only be off the base for the two days remaining to them to publish the magazine. Hulick then visits triumphantly with an intercepted cable about Woodley's disappearance, but faced once again with his black-market contract, agrees to find new orders for Woodley to ship out. Meanwhile, the village is growing with what Joe calls his "cousins," who pilfer bits of building materials and food. When Ed catches him with a stolen crate of gourmet food, the others talk him into allowing a village party, at which Woodley woos Sakiama's daughter, Chieko. Hathaway sneaks in, and after he spots Woodley, the crafty private convinces Hathaway to trade his silence for the inside scoop on the real Tokyo Rose. Since Woodley is bluffing, the Americans scramble to find a Japanese woman who speaks fluent English. The next day, Joe takes Woodley around Tokyo, where the photographer captures images of a destitute people trying to rebuild their country. He later shows the photos to Ed, suggesting a pictorial story to urge the American soldiers to get to know the people they are no longer fighting. As he is tending to the skinned knee of a local boy, Ed spurns the idea as sentimental. Ferguson soon appears, however, and discovers Woodley, and Ed must soothe his superior with a moving account of how the magazine plans to teach GIs to "unlearn their hate." Meanwhile, Joe locates a Japanese-American girl, but her thick Brooklyn accent prompts the boys to give her diction lessons, and hours later, her new accent fools Hathaway. Hulick then arrives with low-level orders for Woodley to be sent to Guam, but the men steal Hulick's own stateside discharge. The next day, the men and Chieko see Woodley off, but soon realize that he has mistakenly left with the magazine layout. Just then, Hathaway sneaks in and hears "Tokyo Rose" speak. The men imprison him in the closet, and soon after, Woodley rushes back in with the pictures just in time for the magazine to go to print. Fuller loves the issue, but soon after discovering that the Yank staff has been living off the base and stealing rations from all over the Army, storms into Sakiama's, vowing to court-marital them. Counter-intelligence interrupts him, however, inquiring about a photo Woodley's took of a woman in a bread line, as she is suspected of being Tokyo Rose. Woodley is forced to come out of hiding, and although he cannot remember where he took the picture, Joe enters with the woman in the photo in tow. The next day, as the Yank staffers prepare to return home, they watch as Joe swindles Hopper out of money and food in exchange for a room.