Lily Kawamura McGurn and her young daughter, Mini, walk along a country road, talking about “papa,” whom Mini has not seen in a long time. A dozen years earlier, in 1936, theater projectionist and union organizer Jack McGurn sets off a smoke bomb in a Brooklyn, New York, theater, but is outraged when his fellow unionists ignite a fire bomb that endangers patrons. He burns his hands trying to put out the flames. After the union fires Jack, coworker Augie Farrell explains that by staying to fight the fire, he made himself identifiable and endangered the union. In the Little Tokyo neighborhood of Los Angeles, California, theater operator Hiroshi Kawamura hosts a party for a visiting Japanese dance troupe. A Japanese immigrant, or “Issei,” Hiroshi introduces his six American-born “Nisei” children, including teenage daughter Lily Kawamura, considered a beauty in the community. During the festivities, Hiroshi’s film projectionist, Mr. Ogata, is shamed when everyone sees his young wife in the embrace of an entertainer. Arriving in Los Angeles, Jack visits his brother, Gerry McGurn, and Gerry’s wife, Marge. Over dinner, Gerry and Jack argue about politics, and Gerry accuses his brother of being a “Red,” but Jack claims he just wants to find a job. Meanwhile, at the Little Tokyo social club where he gambles, Hiroshi Kawamura laments that his indebtedness has grown because Japanese-American youngsters want to see American movies, not the Japanese movies he plays at his theater. Mr. Fujioka, a prosperous widower, offers to cover Hiroshi’s debts in return for permission to marry Lily. Hiroshi and his wife take their daughter to meet Mr. Fujioka and his mother, but Lily is disgusted with the older man. Jack McGurn gets a temporary job as Hiroshi’s film projectionist when Mr. Ogata commits suicide over his wife’s infidelity. Hiroshi’s son, Charlie Kawamura, befriends Jack and introduces him to Little Tokyo culture. When Charlie stops at a garment shop where his sister Lily works as a seamstress, Jack is smitten, and convinces her to accompany them to a Chinese restaurant. While Charlie runs back to the theater to lock the doors, Lily explains to Jack that her father merely runs the theater, because immigrant Japanese cannot own property in California. Jack asks permission to kiss her, and Lily complies. Later, Jack goes dancing with Lily, and takes her to the projection booth in the empty theater to drink the last of Mr. Ogata’s sake. Jack tells Lily he worked in Brooklyn as a “sweatshop lawyer,” a labor organizer who knows all the government regulations that protect workers. Again they kiss, but Jack sends Lily home before they become more intimate. When Hiroshi learns about the relationship, he fires Jack and orders him to stay away from his daughter, despite Jack’s declaration of love. While Jack gathers his belongings from the projection room, Lily joins him and they make love. On a country road in the present, Lily explains to Mini how she and Jack had to marry in Seattle, Washington, because intermarriage was illegal in California. Lily remembers her mother refusing to speak to her when she left home. After a civil ceremony, she and Jack come upon a wedding party, join the festivities, and have so much fun they almost believe the party is theirs. When Mini is born on Christmas Day, 1938, Jack works in a fish cannery on the docks. Though he talks to a coworker about management exploitation and the need for worker solidarity, Jack avoids joining a strike. However, when the bosses dump a load of fish on the strikers and badly injure one of them, Jack challenges them by reciting labor laws. Lily is angry at her husband’s activism, fearful he will lose his job, but Jack distributes union leaflets and joins a picket line. When policemen attack the demonstration, they throw Jack in jail for assault. Lily, left home alone, takes Mini to Los Angeles. As a plainclothes detective interrogates Jack about his Communist sympathies, he informs the labor activist that Japanese airplanes bombed America’s Pearl Harbor naval base in Hawaii that morning. Lily arrives in Little Tokyo as Federal Bureau of Investigation (FBI) agents ransack her parents’ home, because her father has maintained ties with Japanese cultural groups. Hiroshi is jailed at Terminal Island near Los Angeles. At first, Lily’s mother refuses to speak to her, but when she sees Mini, she embraces the little girl. By the time Jack returns to Little Tokyo, the U.S. government has rounded up many Issei, and Lily’s brother, Harry, claims the Nisei are next, regardless of being native-born Americans. During lovemaking, Jack pledges his devotion to Lily. Later, he takes Mini to visit a department store Santa Claus, but the man refuses to let the little “Jap” sit on his lap. When Jack becomes upset, store managers threaten to call police and order him to leave. During Christmas dinner with the Kawamuras, Jack sings a Japanese song he learned while projecting movies at Hiroshi’s theater. Over the following days, whites rampage through Little Tokyo, destroying property. “We thought we were Americans,” Lily tells Jack. President Franklin D. Roosevelt’s Executive Order 9066 decrees that Japanese Americans have six days to sell their belongings and report to evacuation trains with no more than seventy pounds of property apiece. During the family’s “evacuation sale” of furniture, Mrs. Kawamura burns her mementos, and the children make a game of smashing all the Japanese shellac 78-rpm records. Jack accompanies the family to the train, and tells Lily he will find her after he reports to his parole officer in Seattle. After the train leaves, Jack walks through the ghost town of Little Tokyo, and when he returns to the empty Kawamura house, local children are ransacking the backyard chicken coops. At first, the Kawamura family lives in horse stalls at a racetrack, but after two months, they are sent to a dusty camp in another state. Seattle police rescind Jack’s parole because he has been ordered to report to the draft board in Tacoma, Washington. At the internment camp, Hiroshi rejoins the family, but other Japanese Americans suspect him of collaborating with the FBI. Shunned and at one point beaten, Hiroshi withdraws into himself. Jack, meanwhile, goes through basic U.S. Army training and, when granted his first leave, hitchhikes to the internment camp to see Lily and Mini. Incarceration has taken its toll on the Kawamuras. Charlie has joined a radical “Banzai” movement that objects to their treatment, and during a clash with guards he is injured and sent to the camp hospital. Hiroshi sits silently at his son’s bedside. After three days, Jack returns to duty, knowing he faces punishment because he was absent without official leave (AWOL) after his first day. Lily and her sisters make army netting, which is classified as “war work,” but when bosses refuse to let Mrs. Kawamura visit because she is an Issei, Lily challenges them. Meanwhile, Charlie, having recuperated, refuses to sign a United States loyalty oath denouncing ties to Imperial Japan. Brother Harry signs it, however, and joins the U.S. Army’s Japanese 442nd Infantry Regiment. When Jack returns to the internment camp, he tells Lily he cannot see her for a while because his unit is shipping out. He visits Hiroshi, now sick in the hospital, and admits to the older man that he is AWOL because he needed to see the Kawamura family, whom he loves. Hiroshi insists that Jack return to his unit, but to keep loving Lily. When Jack returns to duty, his commanding officer is sympathetic to his situation, but claims the Japanese have been interned for their own good. Another officer interrupts to ask if Jack, who is enlisted as Jack McGann, is actually Brooklyn labor organizer Jack McGurn. The man tells Jack he is in “big trouble.” Meanwhile, Hiroshi walks into a dust storm and dies. Charlie is sent to a special camp for troublemakers. Harry is killed in combat in Europe and his medal for bravery is sent to the family. Eventually, in 1944, the U.S. Supreme Court invalidates the president’s executive order and Japanese Americans are free to go home. Charlie “repatriates” himself to Japan. The others have nothing to return to in Little Tokyo, so they move to a cousin’s farm. As Lily walks Mini along the country road, she tells her daughter that 200,000 Japanese were killed in Hiroshima by a powerful bomb that ended the war. As they reach the station, they hear a train whistle. Mini wonders if she and her father will recognize each other. Jack gets off the train and embraces his wife and daughter warmly. They walk together along the dirt road.