Joseph Donelly (Tom Cruise),a young Irishman facing property eviction after his father's death, decides to take revenge on his landlord, Daniel Christie (Robert Prosky). In his attempt to kill him however, he is discovered by Daniel's daughter, Shannon Christie (Nicole Kidman) and is injured by her when he tries to escape. While injured he continues his plans to kill his landlord, but his weapon malfunctions and blows up in his face. Held captive while they treat his wounds (planning to subsequently have him hanged for attempted murder), Joseph tries to escape the house and is caught by Stephen Chase (Thomas Gibson), Daniel's arrogant manager. Joseph spits on Stephen in anger and, disgraced, Stephen challenges Joseph to a duel of pistols at dawn. Meanwhile, Shannon, also Stephen's love interest, is growing dissatisfied with the traditional views of her parents' generation and longs to be modern, even going as far as to disgust her mother and their friends by playing American music on the piano. She makes plans to leave for America to claim land that's being given away for free, and with her help, Joseph is able to escape. Shannon pays for Joseph's passage and he pretends to be her servant. This way, a single young woman is able to travel without question, and Joseph, now aware of the reality of the free land, can reach America to claim land. Shannon meets and talks to a kindly man on the ship about the promise of land and her money issues. He informs her that to claim the free land, she must travel to Oklahoma and race for it along with others. Concerned with the expense of travel, she explains to him that she has no money, only expensive silver spoons. He tells her he will help her find a shop to whom she can sell her silver to.
Upon arriving in Boston, the man who provided advice steals her spoons and is shot by men who seem to have previous trouble with him. The spoons are scattered in the street and stolen by passersby. Calling for help, Shannon is rescued by Joseph, who manages to save her bag and get her out of the streets. Taking charge of their situation, Joseph is led to the community of Irish living in the area and speaks to the man in charge. Through him, they find a room to live in and jobs in a chicken processing plant. Due to Shannon's wealthy background, which is hated by the lower class Irish they find themselves surrounded by, Joseph lies and tells everyone that she is in fact his sister, to save her from being exiled or hurt. Time passes and it becomes obvious that Joseph and Shannon have become attracted to each other, but both keep up a front of hostility. One night, after peeking at Shannon undress, Joseph finds himself sexually frustrated and rushes out and joins in a barehanded boxing match. Winning the match provides Joseph with newfound wealth and becomes somewhat of a local celebrity. Meanwhile back in Ireland The Christie house is burned down by unhappy taxpayers, and they and Stephen announce that they will go to America to find their daughter.
Temporarily, Joseph seems to forget about his goals of obtaining land and spends his money on suits and hats, in a thinly veiled attempt to impress Shannon. Shannon however, continues her work at the plant and mocks Joseph's prized hats. At one point, the pair have a spat and it becomes obvious that Joseph is extremely upset that he's not managed to gain Shannon's approval or admiration. Shannon begins to question Joseph about his plans to get land and his lack of money the night before the largest fight of his career. He replies angrily that he easily earns money and will continue to do so. He spitefully tells her that he earns more money than she could ever dream to. She retorts that she could earn just as much and disappears into their room. Later, right before the big fight, Joseph searches for Shannon, but is unable to find her. He's directed to his fight, told by others that she is there. Rushing to the site, he discovers she has become a dancer at the social club, demeaning herself to earn more money. He attempts to ignore the men pushing him towards the ring and covers Shannon with his jacket, demanding that she stop dancing. Before he can finish with her, the men around plea with him to fight. The Irish men backing Joseph offer him a small fortune ($200) for this one last, great fight. Shannon, who previously scorned boxing, urges him to do it, since it would be enough money to fulfill his wish of traveling to get land. Joseph agrees and begins to fight a large Italian fighter. All goes well until Joseph witnesses one of his backers (a member of the city council) forcing Shannon into his lap and groping her. Completely forgetting the fight, Joseph pushes his way through the crowd to free her. As he is pushed back into the ring his foot crosses the line, signalling he is ready to begin fighting, the Italian then beats Joseph. Because Joseph lost the fight he is then thrown out of the club. When Joseph wakes up he runs out of the alley he woke up in and runs into Stephen Chase asking drunkards if they've seen Shannon. Joseph then runs to his room to find the backers searching the room for their money. When they find it they take it, and throw Joseph and Shannon out into the snow covered street and tells the owner of the "whorehouse" that if she let them stay one night, it will be shut down.
During a very cold night with no food, they become desperate enough to enter a seemingly abandoned house of luxury. Joseph shows signs of sadness at the beautiful things, knowing Shannon has suffered and deserves a better life than she currently has. He encourages her to pretend the house is hers, and offers to serve her. She's moved by this, but begs him to join her instead, and pretend with her, that they are married and the house is theirs. During the tender moment they declare that they 'pretend' to love each other and kiss. At that moment the owners of the house returns and chases them from the property, shooting Shannon in the process. Joseph brings Shannon to Christie's for help after she is shot. Stephen continuously scolds him and ridicules the state Shannon is in. Deciding Shannon will be better cared for here, with her family and wealth, Joseph leaves Shannon with her family, despite his obvious feelings for her.
He then heads west to work on the Trans-Continental Railroad, seemingly abandoning his dream of owning land. After many months, Joseph is confronted by his father in a dream, and is reminded of his desire to own land. Joseph decides to join the wagon trains and arrives in Oklahoma Territory just in time for the Land Run of 1893, which will enable him finally reach his goal. Through chance he discovers Shannon, now healthy and obviously well taken care of, has also arrived. Confronting her, he discovers she arrived on train, riding the very rails he built. She offers him luck, but is rather cold and Joseph leaves disheartened. Stephen, who witnesses the exchange, warns Joseph that he will kill him if he goes near Shannon. Arriving late to the event, Joseph is forced to choose between two horses the unruly stallion or the broken slow horse. He choices the broken horse that gets killed that night he then is forced to ride the unruly horse. Shannon attempts to give him advice, but is quickly ushered away. During the race, Joseph chases after Shannon and Stephen, knowing that Stephen has broken the law and already found a very rich spot of land to claim. During the race, Shannon falls off her horse and Joseph rushes to her aid. Angered by this, Stephen races back towards them, instead of his goal, the land, and attempts to shoot him. They have a brief fight but Joseph manages to knock the gun from him. Shannon encourages Joseph to continue the race. He races Stephen to the land but then Stephen comes along and they have another fight in which Joseph falls to the ground, hitting his head on a rock, mortally wounding him. Shannon rushes to his side and finally rejects Stephen when he questions her actions. Stephen leaves and Shannon is left to try and keep Joseph alive. As he dies, Joseph finally confesses that he loves her, and without her, the land that was so important to him means nothing. He dies, and Shannon mourns, crying over his body. She tells him that she always loved him, from the first moment she saw him. This suddenly revives him, similar to an earlier scene involving his father, and together they happily drive their flag through the ground and claim their prized land.