There Will Be Blood is a movie " loosely " adapted by Paul Thomas Anderson from the 1927 novel OIL! by Upton Sinclair. The movie centers on character Daniel Plainview, played by Daniel Day-Lewis, who starts out as a simple silver miner that comes across oil after blasting in his mineshaft. The movie skips forwards and Plainview has made himself a fairly rich man, a wise and shrewd business/oil man who won't accept just anyone's help. Daniel Plainview is not a very decent person who constantly looks into people and sees their hesitation in helping him get richer. He is a borderline nihilist who doesn't like people and thinks most humans are lazy and ignorant. The point is later conveyed that the only reason he has people in his life is because he couldn't benefit financially if he didn't. Otherwise he could not care less.

While drilling here and there for oil, Plainview gets a hot tip from farmboy Paul Sunday (Paul Dano). Under the guise of quail hunting, he and his son H.W. scout the property and find what Plainview calls "earthquake oil". Hoping he can buy the land for quail hunting purposes, he meets his enemy in the form of a young man of the Word of God: Eli Sunday (also by Paul Dano). While Plainview is discussing land purchase at the dinner table with the Sunday family, Paul Sunday absent, Eli speaks up vigilantly about the oil on the property. Plainview plays ignorant and tells Abel Sunday, head of the household, that if he does find oil they will receive payment. Limited in his role of decision making, being the younger of the Sunday boys, Abel agrees and Plainview goes to work.

A parallel of immorality is drawn between Eli and Daniel as Eli makes himself head of the charismatic church. Plainview sees right thru his righteous claims and attacks the ground beneath his feet with a feverish pace that threatens to milk the land of all it's worth. Tension builds further as H.W. Plainview is deafened in an oil well explosion. H.W. quickly becomes bitter and violent, even going so far as to commit arson on Plainview's alleged brother Henry. The deafened boy is sent away. Next, we see Eli and Daniel together, the Preacher Sunday is asking "When do we get our money, Daniel..." Plainview slaps him to the ground without flinching. His oil wells are producing and he will not be bothered with Eli's whining. The next time we see them together Preacher Eli calls Daniel on his son's dismissal. In a hilariously false display at the church, Plainview is forced to admit that he sent away his child. Sunday ropes him into the whole display after discovering Daniel killed Henry the moment he confessed he was a drifter trying to get by.

After taking his son H.W. back and proving to his business competitors that he can handle an unruly child, the movie skips forward and Plainview is one of the richest men alive during the depression. Even more nihilistic than before, Plainview listens to a grown H.W. tell him that he's going to Mexico to drill for oil there. Plainview instantly sees him as a competitor and tells him for the first time that he's a "bastard from a basket" and his sole purpose was to help Daniel buy land. In a shouting match with H.W.'s interpreter, the two go their separate ways for good.

The last scene is the movie's climax. It involves a down-and-out Eli Sunday and a self-righteous rich Plainview. He strips Eli of his ego and swagger with a quick-witted false promise of drilling "untouched" land. The Preacher Sunday is near a stunned silence during a vicious verbal attack by Daniel. Sunday is beaten to death on the waxed floor of Plainview's private bowling lanes. "I am finished !" are the last words as Daniel calls for his manservant.