Daniel Dillon is an Irish immigrant who settles in the high mountains of California during the Gold Rush of 1849. It is now 1867, and Dillon has a vault filled with gold and a town of his own, named Kingdom Come. Dillon owns nearly every business of consequence in the town; if someone digs for gold, rents a hotel room, opens a bank account, or commits a crime, they will have to deal with Dillon.
One of the few profitable enterprises in town that Dillon does not own is the saloon/brothel, which is operated by Lucia, his Portuguese lover.
Donald Dalglish is a surveyor with the Central Pacific Railroad, which wants to put a train either through Kingdom Come, or somewhere in the vicinity. He is here to decide the route. Dillon is anxious to ensure that the railway line is routed through “his” town, as this will bring more business.
Among the travelers who arrive in town with Dalglish are two women, the beautiful but ailing Elena Burn and her lovely teenage daughter Hope. The presence of these women is deeply troubling for Dillon, for they are the keys to a dark secret Dillon has kept from the people of Kingdom Come for nearly twenty years. Dillon had come to these mountains with his Polish wife Elena and their months-old baby, Hope. On a cold and snowy night they happen upon a shack named Kingdom Come, owned by a disillusioned ’49er named Burn. Like Hardy’s Mayor of Casterbridge, Dillon sells Elena and Hope to the prospector in exchange for the small gold claim that would later flourish and make Dillon so wealthy. Burn has died, and Elena has come to find Dillon because Burn left her with nothing, she is dying, and she wants Dillon to give her $200 per year so that she can “do right by Hope”.
Dillon tells Lucia that they have to end their relationship and gives her some gold bricks and the deeds to her home, the saloon/brothel, and the tobacco house. Lucia is heartbroken, wanting Dillon and not his money. Dillon tells Elena that he never married anyone else because he was always married to her. The two renew their marriage but their time together is short, filled with Dillon’s efforts to find a cure for her illness and ending with her death.
Elena’s death coincides with the decision to route the railway some distance from the town for easier passage and construction. Lucia moves the girls, the booze and the tobacco house to the valley, effectively moving the entire population of Kingdom Come to her new town of Lisboa, named for her father’s home in Portugal, to be near the railroad. Following Elena’s funeral, Hope tells Dillon that she is leaving to find Dalglish and start a life with him. Dillon takes her up to the original shack Kingdom Come, showing her a picture of their family when she was a baby, and revealing the deal made right on that spot between him and Burn. Hope leaves him and goes to the new Lisboa.
Dillon is thus faced with the loss of both Elena and Hope, and his town. He sets fire to all the buildings in Kingdom Come. The smoke attracts the people of Lisboa, who find Dillon’s frozen body in the snow near his original shack. Lucia is devastated, crying over the frozen body as it is brought back to the ruins of Kingdom Come. While many of the ‘former’ townspeople rush to find Dillon’s stockpile of gold in the burned out vault, Hope and Dalglish choose instead to follow Dillon’s body as Lucia and others continue with it down the mountain.