Plot

In 1898, Daniel Plainview (Daniel Day-Lewis), a prospector in New Mexico, mines a potentially precious ore vein from a pit mine hole. Daniel works alone, in the middle of the wilderness under brutal conditions. In the process of dynamiting the lode, he falls and breaks his leg. With the silver sample, he climbs out of the mine, drags himself to an assay office, and receives a silver and gold certificate claim. Daniel expands the mine and pours more resources into digging deeper for the ore.

In 1902, he discovers oil near Los Angeles and establishes a drilling company. At first, the extracted oil is stored in a pit dug nearby, and Daniel designs his own oil rig to extract the oil. Following the death of a worker in an accident (the worker was in the oil well, when the rig being used to extract the oil collapsed on top of him), Daniel adopts the man's orphaned son. The child was barely a toddler, and Daniel mixes a little alcohol in milk to get the child to sleep.

After a few years, Daniel refers to the child, H. W. (Dillon Freasier), as his business partner, which allows him to present himself to potential investors as a family man who wife died in childbirth. Daniel's oil well is already producing 2000 barrels a week, producing an income of $5000 every week. He has 2 more wells under development. Daniel approaches landowners who have recently discovered oil & says that he does not rely on contractors to do the drilling as he does his own drilling with his own men. Daniel says that normally, 1 in 20 prospectors have a chance to become oilmen, but with his connections and his knowledge, he says that he can start producing oil in under a week, once the leases are signed. He offers a 16.67% royalty on all income and a production linked bonus to the landowners.

In 1911, Daniel is approached by Paul Sunday (Paul Dano), who tells him of an oil deposit under his family's property in Little Boston, California. Fletcher Hamilton (Ciaran Hinds) works with Daniel as his right-hand man. Paul also adds that Standard Oil is buying farms in the area and provides more data to convince Daniel that oil is indeed available underneath the property. Paul takes $600 to divulge this information and the address of his family ranch.

Daniel travels to the property himself with HW, disguised as Quail hunters and campers. They camp on the Sunday ranch as Daniel conducts his surveys. Daniel finds evidence of oil on the surface and knows that there is a lot more underneath. Daniel plans to build a pipeline to the coast to transport the oil, so he is not wasting money on shipping costs.

Daniel attempts to buy the farm at a bargain price of $3700 (as the family doesn't know that oil has been discovered on the property). However, Paul's twin brother Eli (Paul Dano) demands $10,000 for the church, of which he is pastor. Eli says that he knows the ranch has oil, which sits closer to the surface. An agreement is made for $5,000 after the well begins producing, and Daniel acquires all the available surrounding land, except for one holdout: William Bandy (Hans Howes).

Oil production begins, but an accident kills a worker, and a gas blowout deafens H. W (Russell Harvard). Eli blames the disasters on the well not being properly blessed. Daniel refused Eli's offer to bless the well at its inauguration in front of the whole town. When Eli demands the $5,000 that Daniel still owes, Daniel beats and humiliates him. At the dinner table, Eli berates his father for trusting Daniel.

A man arrives at Daniel's doorstep claiming to be his half-brother, Henry (Kevin J. O'Connor). Daniel hires Henry and the two grow close. H. W. sets fire to their house, intending to kill Henry. Angry, Daniel sends him away to a school for the deaf in San Francisco. A representative from Standard Oil offers to buy out Daniel's local interests, but Daniel strikes a deal with Union Oil and constructs a pipeline to the California coast, though the Bandy ranch remains an impediment.

While reminiscing about his childhood, Daniel becomes suspicious about Henry's story and one night quizzes him about it at gunpoint. "Henry" confesses that he was a friend of the real Henry's, who died from tuberculosis, and that he learned the details of Henry's life by reading his personal journal. In a fit of rage, Daniel murders the impostor and buries his body.

The next morning, Daniel is awakened by Bandy, who knows of the previous night's events and wants Daniel to repent. He also wants Daniel to baptize and that's the only way he will allow Daniel to build the pipeline. At the church, as part of Daniel's baptism, Eli humiliates him, strikes him, and makes him confess to having abandoned his son, before announcing to the congregation that Daniel will be making a large donation to the church. With the pipeline underway, Daniel arranges for the still angry H. W. to return, while Eli leaves town for missionary work.

In 1927, H. W. marries Mary (Colleen Foy), Eli and Paul's sister. Daniel, now extremely wealthy but suffering from alcoholism, lives as a recluse in a large mansion. Through a sign language interpreter, H. W. asks Daniel to dissolve their partnership so that H. W. can establish his own oil company in Mexico. Daniel reacts brutally, mocks H. W.'s deafness, and reveals H. W.'s true origins as an orphan. H. W. thanks God he has "none of Daniel in him" and leaves.

Eli visits Daniel, who is drunk, in Daniel's private bowling alley. Eli, now a radio preacher, offers to sell Daniel drilling rights on the land of William Bandy, who has recently died. Daniel agrees on the condition that Eli denounce his faith and his own credibility. Eli reluctantly does so. Daniel reveals that the property is now worthless because he has already drained its oil by slant drilling from surrounding wells. Shaken, Eli confesses to being in dire financial straits and to having strayed morally. Daniel taunts him, chases him around the bowling alley, and beats him to death with a bowling pin. When his butler enters the room, he finds Daniel sitting on the floor as he mutters "I'm finished!"