A coal miner yells “Fire in the hole!” before he sets off a dynamite charge. Other miners lie prone on a conveyer belt as they ride deep into a coal pit to begin their shift. Inside, they set blocks to hold up the low ceiling while a machine cuts coal with a spinning blade that is sprayed with water to keep down the dust. The same conveyer belt that brought the miners in carries coal out to the tipple. A former miner, Nimrod Workman, sits on his porch, singing about the dangers of the job and talking about the old days when a foreman put a pit mule’s safety above that of his men because the animal was harder to replace. When the miners at the Brookside mine in Harlan, Kentucky, vote to join the United Mine Workers of America (UMWA) in June 1973, the owners—Duke Power Co. of Charlotte, North Carolina, and its subsidiary, Eastover Mining Company—refuse to sign the UMWA contract, because Duke Power only recognizes the Southern Labor Union, which is controlled by the coal companies. The Brookside miners go on strike. A miner's wife, Bessie Lou Cornett, talks about how her grandfather, a union man who died of "black lung" disease, taught her to hate the coal companies. Meanwhile, a union organizer with a speaker on his truck drives through town, telling residents to support the strikers on the narrow highway leading to the Brookside mine. In an old film clip, early UMWA president John L. Lewis says that the solitary worker is powerless against the resources of a company and therefore needs the aid of a union of fellow workers. A Brookside mine foreman named Basil Collins says the unions are filled with "known communists" out to destroy the country. Old men recall being paid six cents an hour for fourteen-hour days inside unsafe mines, and claim that the state government, the Catholic Church and the old union worked with coal officials against the miners. Whenever striking workers turned to violence to defend themselves against hired thugs, state troopers or the state militia always supported the companies. Black and white film footage shows army troops occupying coal towns in the 1920s. In the early 1930s, Harlan County was known as "bloody Harlan" because of routine beatings and killings, until a major shootout in 1931 brought state militia troops into the county to end the violence. In July 1973, in the first month of a new strike, state policemen stand between picketing miners and their replacement workers driving to the mine. Eastover has obtained a court injunction preventing miners from blocking the road and from calling the strikebreakers "scabs," an incendiary term. In response, miners’ wives at the Brookside Woman’s Club discuss how they can support their husbands. Since they are not covered by the injunction, half a dozen women, including Bessie Lou and her mother, Lois Scott, lie down on the road to block the scabs' cars going to the mine. They are arrested and taken to jail, and, at trial, Bessie Lou complains to the judge that there are two kinds of law in Harlan County: one for the company and one for the workers. At a news conference, Norman Yarborough, president of Eastover, defends his company’s anti-UMWA policy and says he would hate to see his own wife revert to the shameful behavior of the miners’ wives. Union official Houston Elmore describes the local economic system as "feudal." Several miners, including Jerry Johnson, travel to Manhattan where they pass out pamphlets on Wall Street and tell stockbrokers that Duke Power is a "risky" investment. Johnson gets into a discussion about working conditions with a New York policeman, whose salary and benefits are far greater than those of any Kentucky miner. At a Duke Power stockholders meeting, miner Bill Doan challenges the president, Carl Horn, and defends the miners’ right to strike. A superimposed graphic shows that coal company profits are up by 170 percent, while miners' wages haven’t kept up with the seven-percent inflation rate. A former U.S. Bureau of Mines president, John O’Leary, claims that American mining companies have a terrible safety record, and that the bureau itself has a poor record of regulating them. Several years earlier, in 1968, the Mannington coalmine in neighboring West Virginia ignored the findings of sixteen Bureau of Mines safety inspections and an explosion there killed seventy-eight miners. At a "black lung clinic," older miners take stress tests to determine the diminishment of their lung capacity due to their prolonged exposure to coal dust. One man says that crossing a room makes breathing difficult. Dr. Hawley Wells, Jr., an early researcher in black lung disease, displays a piece of lung tissue from a miner; it crumbles in his fingers. A company attorney states that coal dust does not "necessarily" impair miners’ "pulmonary function." In 1969, longtime UMWA president W. A. "Tony" Boyle was challenged in a union election by Joseph "Jock" Yablonski, who accused Boyle of colluding with the coal companies. After Boyle defeated Yablonski in what was considered a crooked election, Yablonski called for a government investigation into UMWA fraud. Within days, three men murdered Yablonski, his wife and his daughter. Boyle was subsequently arrested for hiring the killers and sent to prison in 1974. By then, new UMWA president, Arnold Miller, had promised a reformed rank-and-file union run by rank-and-file workers. In Harlan County, the strike is in its tenth month and the strikers are still on the road at Brookside, but thugs led by Collins brandish clubs and guns, forcing their way through the picket line in pickup trucks. At a union meeting, Florence Reese, an aging miner’s widow and a veteran of the violent labor struggles of the 1930s, sings a song she wrote called "Which Side Are You On," which has become a union standard over the years. A coal miner's house is shot at, leaving several holes. As the pickets begin to thin out, UMWA official Bernie Aronson delivers a speech to remind the miners that if there weren’t so much at stake, the company wouldn’t be fighting them so hard. At the Brookside Woman’s Club, Sudie Crusenberry is elected president, but the real leader is Lois Scott, who proudly pulls a pistol out of her bra. When company thugs fire at the women on the picket line one night, Lois tells the wives it’s time to meet violence with violence. To insure secrecy, she and strike leader Bob Davis refuse to divulge where tomorrow’s picket will be until they meet at Mack’s at five a.m. The next morning, they push a disabled car onto a railroad track that crosses the narrow highway to the mine, blocking both the scabs and the coal trains. The women and their husbands have armed themselves with rifles and pistols to fend off Collins’s goons. The miners then ask Sheriff Billy G. Williams to serve Collins a warrant that they obtained against him for brandishing a weapon. When Williams serves Collins, he and his strikebreakers turn their vehicles around and leave. Later on, busloads of UMWA members from surrounding states arrive in Harlan County for a parade and festival to support the local miners. Arnold Miller gives a speech and musicians sing about labor glories. But, after the visitors leave, a miner laments that the union should have taken advantage of its gathered members by marching to the mine in a show of force. One night soon afterward, a scab named Bill Bruner walks up to a miner named Lawrence Jones and shoots him in the head. At a union meeting, several miners and wives call for going after Collins and his thugs, but an older man calls for restraint. Following Jones’s well-publicized funeral, Duke Power accepts the UMWA contract. Bernie Aronson says the murder helped seal the deal, but that the length of the strike, the escalating violence and the national anti-Duke publicity were also factors. The new contract lasts three months before the national union contract expires, requiring the Brookside miners to ratify a new one. In 1974, the UMWA goes on strike for three weeks against the Bituminous Coal Operators Association to reach a new agreement, and 100,000 miners return to the picket lines in 1975 to protest the way that companies abuse grievance procedures. Some miners complain about UMWA's current leadership, but overall, working conditions and pay for the Eastover Mining Company employees have improved considerably.