Hal Philip Walker, Replacement Party candidate in the 1976 United States presidential election, arrives in Nashville for a fundraising gala. Meanwhile, two recording sessions are taking place in a nearby studio: in one room, country superstar Haven Hamilton records a patriotic song commemorating the Bicentennial, while next door, Linnea Reese, a white gospel singer, records a song with the Jubilee Singers of historically black Fisk University. Opal, an Englishwoman who claims to be working on a documentary for the BBC (though she refers to the British Broadcasting Company), attempts to listen in on the sessions.
Later that day, country singer Barbara Jean returns to Nashville following what the crowd believes was a burn accident (which may actually have been a nervous breakdown and stay at a mental hospital). She is greeted at Berry Field by local industry elites, including Haven and his companion, Lady Pearl, a nightclub owner. Also present are Pfc. Glenn Kelly, who is obsessed with Barbara Jean, and a popular folk trio consisting of married couple Bill and Mary, and guitarist Tom, who are in town to record an album. Meanwhile, Martha, a teen groupie going by the name "L.A. Joan", is picked up by her uncle, Mr. Green, at the airport; she has arrived to visit her dying aunt Esther, but covertly plans to pursue musicians. In the airport cafe, African-American cook Wade Cooley and his co-worker, a waitress named Sueleen, discuss her aspirations to become a singer.
On the tarmac, Barbara Jean collapses from heat exhaustion, and those in attendance depart the airport only to become stranded after a vehicle pile-up occurs. During the commotion, Winifred, an aspiring country singer, runs away from her husband Star; Star then gives a ride to Kenny Frasier, who has just arrived in town carrying a violin case. Opal takes advantage of the traffic jam to interview Linnea, as well as Tommy Brown, an African-American country singer. That night, Sueleen performs at an open mic at Lady Pearl's club, demonstrating no singing ability. Meanwhile, Linnea's husband Del has John Triplette, Walker's political organizer, over for dinner. Throughout the meal, Linnea mainly focuses on communicating with her two deaf children. Tom, who crossed paths with Linnea a few weeks earlier, phones the house to ask Linnea on a date, but she dissuades him. Glamorous singer Connie White performs that night, in lieu of Barbara Jean at the Grand Ole Opry. Mary misses Connie's performance to Bill's dismay, instead having sex with Tom at the hotel. At the hospital, Barbara Jean argues with her manager husband Barnett over Connie replacing her, and he accuses her of having another nervous breakdown.
On Sunday morning, Lady Pearl, Wade, and Sueleen attend a Catholic mass, while Linnea sings in the choir of a black Baptist church. In the hospital chapel, Barbara Jean sings "In the Garden" from her wheelchair while Mr. Green, Pfc. Kelly, and others watch. Opal wanders through a massive auto scrapyard, recording observations on a tape recorder. Haven, Tommy, and their families attend the stock car races, where Winifred unsuccessfully attempts to sing on a small stage. Bill and Mary argue in their hotel room and are interrupted by Triplette, who recruits them to perform at the gala, while Tom tries to get chauffeur Norman to score him drugs.
After Barbara Jean is discharged, she gives a performance at Opryland USA that ends in her being pulled off stage as she rambles between songs. To remediate her poor performance, Barnett pledges her to perform at Walker's gala. Martha meanwhile agitates Kenny, who is renting a room in her uncle's house, when she attempts to open his violin case. At Lady Pearl's club that night, Linnea, Martha, Bill, Mary, Opal, Norman and Wade are among those attending an open mic. Tom sings "I'm Easy" and Linnea, moved, goes back to his room, where they have sex. Tom is accustomed to women becoming clingy and emotional after trysts but Linnea is polite but detached afterwards. She leaves Tom's room oblivious to his blatant attempts to rattle her and make her jealous, frustrating him. Meanwhile, at an all-male Walker fundraiser, Sueleen is booed off stage for singing poorly; Del and Triplette convince her to perform a striptease in exchange for a slot at the gala. A drunken Del later comes onto Sueleen, but Wade rescues her. He tells her that she cannot sing and attempts to persuade her to come to Detroit with him; she refuses, determined to "sing with Barbara Jean".
The next morning, the performers and audience converge at the Parthenon for Walker's gala concert. The lineup consists of Haven, Barbara Jean, Linnea and her choir, Mary and Tom, and Sueleen; Winifred arrives, hoping to sing. Meanwhile, Mr. Green and Kenny arrive at the gala searching for Martha, who has failed to attend her aunt Esther's funeral, and find her accompanying Bill. During Barbara Jean's set on stage, Kenny produces a gun from his violin case, and begins shooting at the stage. Barbara Jean is shot; a bullet grazes Haven's arm. Chaos breaks out. Kelly disarms Kenny. Barbara Jean is carried off the stage, bleeding and unconscious (or dead). Haven tries to calm the crowd by exhorting them to sing, asserting that "This isn't Dallas.” Being wounded, he gives over the mike to Winifred, who haltingly begins singing "It Don't Worry Me", eventually joined by Linnea's gospel choir also on stage.
