The narrator tells how Nikola Tesla, as a small child, saw electricity when petting his cat. In 1884 New York City, adult Nikola Tesla (Ethan Hawke) is working for Thomas Edison (Kyle MacLachlan), who doesn’t seem to regard Tesla overly highly. He is told by another coworker that perhaps it is because Edison’s wife has just died. When they get into a heated work confrontation, they smash ice cream cones in each other’s faces.
The narrator revealed to be Anne Morgan (Eve Hewson), appears with a laptop, saying that this probably is not how this happened. She tells about how when you Google Tesla, you only find a couple of photos, and proceeds to detail more information about his past and how he had his first flash of the motor he would eventually invent. She notes when you google Edison, you get twice as many results.
The narrator continues to explain his previous troubles and financial poverty until he is finally able to pitch his idea to those who will pay him much more than Edison. The narrator tells how Edison meets his second wife Mina (Hannah Gross) in 1885. Tesla continues work on his induction motor, assisted by his friend Anthony Szigeti from Budapest (Ebon Moss-Bachrach).
They reveal their spark-less motor to high praise, and Tesla eventually meets Anne, the daughter of JP Morgan (Donnie Keshawarz). Tesla presents his findings, and George Westinghouse (Jim Gaffigan) buys the patents for Tesla’s inventions and brings Tesla to Pittsburgh to oversee production. Westinghouse updates Tesla on the rivalry between Edison’s findings and Tesla’s, Edison insists on his for the matters of execution. Edison says direct current is better and dismisses Tesla’s alternating current.
Szigeti shows Tesla an invention he has discovered, a compass, only to be told by Tesla another inventor has beaten him to it, and he leaves town to seek other fortunes. Meanwhile, William Kemmler becomes the first person to be executed with electric induction – but it is completely botched and gruesome. Edison blames the doctors. Tesla begins dating Anne – despite her father being one of Edison’s incredibly wealthy funders.
After the World’s Fair in 1893 is powered by Westinghouse/Tesla’s machines, everyone sees Tesla’s alternating current as highly viable. Edison meets with Tesla and admits he was wrong and asks him to work together, insisting bygones be bygones. The narrator comes over and says the meeting never happened, and that Edison never admitted he was wrong and they never reconciled.
Westinghouse tells Tesla that Edison is sunk, but that their business is still failing, and that they need a JP Morgan-like merger. If Westinghouse pays Tesla what he is owed, he will be bankrupt. The only merger he could get requires Tesla to give up his horsepower clause, but then the entire country will be using his machines. Tesla chooses to tear up their contract to go forward with the merger.
The famous traveling actress Sarah Bernhardt (Rebecca Dayan) performs her act and everyone goes out to see her. After the performance, Tesla seems attracted to Sarah, concerning Anne. Tesla and Edison have an uncomfortable and tense run-in where Edison seems bitter and resentful of Tesla’s success, and Edison leaves with Sarah’s group.
After discussing Tesla’s work with her father, he asks whether Tesla is seeking an investor or a wife. Shortly after, Tesla tells Anne he is planning on moving to Colorado, rather far. There, he begins work developing the Tesla coil. Its debut is impressive and unsettling, blowing up the local generator, which Tesla offers to pay for.
Tesla once again sees Sarah when her tour comes through town and the two have an attraction. Tesla then presents his discoveries to JP Morgan showing him all the advantages his machines can provide the world. He is skeptical and doesn’t like Tesla very much, but invests one hundred thousand dollars into Tesla’s work.
The narrator reveals Edison got out of the electricity business and goes into mining – which ends up being a complete failure that loses him four million dollars. After Tesla gives an interview saying his equipment is picking up signals that could potentially be from Mars, Anne confronts him about this idea, noting her father reads the interviews he gives.
Tesla goes to Morgan to ask for more money, who is skeptical that Tesla’s research is really going anywhere. Tesla explains he is developing technology to map brain waves from the brain. Morgan, who is playing tennis with Anne, dismisses him. In a fantasy sequence, Tesla sings “Everybody Wants to Rule the World”.
The narrator Anne asks Tesla if he remembers her face when she realized it was hopeless between them. She moves to the French countryside and begins working on creating health services and camps for children. She explains that Tesla outlives Edison, Westinghouse, Bernhardt, and Morgan and dies alone at 87. She says that maybe he overreached, or maybe the world we live in is one that Tesla dreamed first.