Act I

Scene one: Ellis Island, Early 1900s

A Greek immigrant named Cyril Kephalus has just arrived in America with his five year old daughter Doria, and his friend Louis Tikas. They are discussing where to go to try to find work when another Greek immigrant named Niko tells them about a mining town in Colorado called Ludlow where they are eager to hire new immigrants to work in the coal mine. They are excited with the prospect of opportunity, and resolve to go there together.

Scene two: Pueblo Train Depot

They arrive in Colorado and are greeted by Niko's cousin Anna. She introduces them to many other immigrants, including one Juan Hernandez and Charlie Costa, but explains that it is hard to talk people in Ludlow because of the lack of a common language. Some of the immigrants complain that the company does nothing to address this problem.

Scene three: In the church, Jan. 5, 1913.

Thirteen years have elapsed. Inside St. John the Baptist Greek Orthodox Church, Father Papageordopoulos delivers a sermon. He thanks the company for all that they provide and ominously exhorts the workers to remain calm during difficult times. After church, the exiting congregation is met outside by a union leader who counteractively tells them that they deserve to be treated better by the company. He urges them to take matters into their own hands.

Scene four: Mineral Palace Park

A group of people are ice skating on Mineral Palace Park lake. Among them are a company executive named Lamont Bowers, and a young manager named William Phelps. As they are skating, the ice suddenly cracks and Lamont falls into the cold water. Doria, who is passing by on a stroll, helps William rescue Lamont. As he is carried off by paramedics, Doria and William flirt, but she is troubled when she finds out that he is management, so she leaves abruptly.

Scene five: Gus's Tavern

Workers complain about their deplorable working and living conditions, and seriously discuss the possibility of a strike. They elect Louis as their leader. Niko complains about being single, and convinces Cyril to pledge Doria's hand to him in marriage. Cyril gives him his great-grandfather's war medal to secure his promise.

Scene six: Mineral Palace Park

William and Doria are back at Mineral Palace Park. They decide to keep their burgeoning love a secret because of the growing tensions between Doria's father and William's bosses. They are interrupted by Doria's friend Ruby and her son Joshua. Ruby explains that once the men go on strike, the company will kick them out of their homes, but the union will help them establish a camp.

Act II

Scene one: At the Ludlow Tent Colony

The men have gone on strike, and dawn breaks in the newly established tent colony at Ludlow. Ruby is up early, singing a lullaby to Joshua as he sleeps. When he awakens he is hungry, but is denied breakfast because of short supplies in the camp. He goes off to the school that Doria has established, where children of many nationalities come to learn and play together, ignorant of their differences. After class, Cyril enters and tells Doria that he has arranged for her to marry Niko. Doria is shocked, but tells him that Niko has been missing for three days.

Scene two: Another part of the camp

Charlie complains that someone stole his food rations, and ascribes it to racial malice. He tells a rumor that Niko has betrayed them and gone back to work in the mine. Juan finds the food rations, along with Cyril's great-grandfather's war medal. They blame Cyril for the theft, not knowing that Cyril had given the medal to Niko. Charlie, infuriated, exacts petty revenge by telling Cyril that Doria has been seeing a company manager. As Cyril and Doria scramble to explain themselves, Anna enters crying, because her cousin Niko has been found dead, evidently murdered.

Scene three: Inside the Mineral Palace.

Ruby is singing at a company ball. William and Lamont discuss the strike, and Lamont takes a harsh stance regarding the workers' rights. He confirms that Niko had come back to work in the mine, and mentions that he had bribed Niko to steal the food rations in an attempt to disorganize and weaken the strikers by creating racial tension amongst them. He tells William that the governor has ordered in a militia to deal with the strike. Lamont advises William to stay away from Doria, but William goes on daydreaming about her.

Scene four: At the Ludlow Tent Colony

Doria reciprocally daydreams about William, but she is interrupted when her class starts to arrive. Joshua tells her that the militia has arrived, and the men of the camp have taken arm. Ruby comes to tell Joshua that her husband Sam has been wounded in the struggle, and Joshua comforts her. Joshua goes off to fight, and Doria resumes her daydreaming.

Scene five: A deserted area outside of the camp

Lamont accuses Louis of kidnapping a replacement worker, but Louis denies it. Their argument is broken up by the sound of gunfire. Louis runs to Cyril and, aware of the increasing gravity of the situation, advises Cyril to evacuate the women and children from the camp on the next passing freight train. Cyril delegates this responsibility to Doria, but she resolves to stay and fight. She tells him that Charlie has dug a pit under his tent where she can hide.

Scene six: The Camp

Full scale fighting has broken out. The militia lights the camp on fire and murders Louis. Once the fighting subsides, Cyril discovers several bodies, including his daughter's, in the pit under Charlie's tent: They had become trapped there when the fire began and burned to death. William comes to check up on Doria, and Cyril blames him for her death, and murders him in revenge. Later, separate funerals are held for the two lovers, but one song unites them in the end. Back in the Mineral Palace, Ruby sings that King Coal and the Silver Queen will live on in good memories that will erase past animosity.