NOTE: This spoiler was submitted by Spectre.
We open in the 1960s where J. Edgar Hoover (Leonardo DiCaprio) is dictating his autobiography to a series of young FBI agents, the first being Agent Smith (Ed Westwick). Hoover rails that he saw through the initial fight of communism, and that communism is not a political party but a corruption of the soul. “Even good men can be corrupted,” Hoover says.
Hoover starts in 1919, talking about his first boss in the Bureau, Mitchell Palmer (Geoff Pierson). Mitchell was at home one night when a radical of the communist movement bombed his home. Lucky for Mitchell, he, his wife, and daughter were not harmed. According to Hoover, he drove up on his bike and watched as evidence was destroyed and contaminated by normal police procedure. Hoover grabbed up a few pages of the communist leaflets and left. Hoover relates to Smith he wasn’t actually there but they need to build a narrative in which to tell the story. Smith says they will say a man matching Hoover’s description was at the scene.
Hoover is walking in the bureau when he passes a group of secretaries. The eldest introduces him to the newest one, Helen Gandy (Naomi Watts). Hoover says hello and wishes “Ms. Gandy” well in the bureau, then heads home.
Hoover still lives with his mother Anne (Judi Dench). His father is in the last stages of dementia and is barely coherent. We see a flashback of young Hoover in which his mother says he will one day rise to be the most powerful man in the country.
Hoover talks to Anne telling her work went well and that he is going on a date with Helen Gandy, thinking their dates are going towards a relationship. He is going to show her the card catalog system he created in the library. Anne wishes him well and Hoover goes to change.
Hoover takes Helen to the library and shows her the system to find a book quickly. Though odd, she seems to find the act by Hoover slightly charming. He relates to Helen the idea of a fingerprint system so people could be identified and thus be stopped after they committed crimes.
Hoover drops to one knee and hastily proposes marriage to Helen. Helen thinks he is mocking her and tells him to stand up. She reveals she has no intentions of getting married and wants her career to come first. Hoover understands and offers her to become his personal secretary. Helen agrees, and they head off now as platonic friends.
We cut back to Agent Smith and Hoover in the present day. Smith asks if he wants to talk about 1920. Hoover agrees and continues his story.
Hoover relates that Mitchell and his other superiors hated communists as much as he did. But their office had little power and they could only use the deportation of foreigners as a weapon against radicals. Hoover knew that if he could take out Emma Goldy, a known radical, it would impress his bosses.
Hoover sets up his own task force with Helen and a few agents to set up a card system for communists and suspected radicals. Hoover says they need to do it in such in a way that no one could ascertain what the information is about.
The Bureau was different in the old days. Agents had no power to arrest, they could not carry weapons, and they had no scientific labs. So Hoover had to find ways around the rules to keep him and his agents safe as well actually solve big crimes.
After discovering a communist command center, Hoover and his agents coordinate with local police that could actually arrest. Hoover gives all his men guns as gifts, saying there is no rule about having their own (getting around the not being armed rule). They storm the hideout and arrest all inside. Hoover discovers the communist leaflets were the same ones that were found outside Mitchell’s home. This gives the courts enough evidence to deport Emma Goldman, earning the respect of his bosses.
Despite this triumph, Mitchell was fired for going after radicals so aggressively. Hoover was spared because he was following Mitchell’s orders as a young agent.
Hoover takes a meeting with the Attorney General, who offers him to be acting Bureau chief. Hoover agrees as long as the Bureau gets powers to arrest, carry firearms, and have promotions and appointments based on character and qualifications. Furthermore, the Bureau would only be responsible to the Attorney General. To his surprise, the AG agrees to all of Hoover’s demands saying he wouldn’t have given him the job unless he asked for those things.
Hoover is out to dinner with friends when he introduced to Clyde Tolson (Armie Hammer). They exchange business cards and Hoover is definitely intrigued by the man.
Hoover, along with Helen, inspect a new crop of agents. Hoover tells them they need to cut all vice from their life because at the Bureau they must be free of anything that people could use to question their character. Hoover dismisses several agents he feels doesn’t live up to his standard, including a man he knew from his first days working at the Bureau.
Hoover and Helen go over applications for new agents. Hoover has passed on over 300 applicants for various reasons, from lack of commitment to the agency, to having families. Hoover asks Helen if Tolson sent in an application. Helen says he has but seems to have no interest in joining the Bureau. Helen also notes according to his profile, he seems to have no interest in women. Hoover tells her to set up an interview with Tolson.
Hoover is doing push-ups when Tolson arrives for his interview. He tells Tolson to sit down and Tolson hands him a handkerchief as Hoover is sweating. Tolson sits down and explains that he does want to go into private practice. However, if he is afforded the right opportunity, he would change his mind. Hoover hires him.
Back with present day Hoover, he is taking a meeting with Robert Kennedy (Jeffrey Donovan). The year is about 1961. RFK is the attorney general at that time. Hoover is quite intrigued with Kennedy’s fireplace, finding it grand. Kennedy is enraged that Hoover has possession of illegal wiretaps and is using them to blackmail Kennedy for more power. Hoover is modest, saying he was only following orders. He could have no idea that he would catch his brother John having sex with an actress (an allusion to the rumor that JFK slept with Marilyn Monroe). Kennedy asks for the transcripts and Hoover tells him that he still has a copy of his own for safekeeping.
Back in the past, Hoover learns from Helen that one of his agents, Caffrey, was killed while trying to stop one of the “Public Enemy” bank robbers. Hoover laments to the agent typing for him that the public began to think of the robbers as folk heroes and thought the police was foolish. This is shown most pointedly when Hoover gives an address to the nation at movie theaters. People boo him and the projectionist cuts him off mid-sentence to start the movie that glorifies gangsters.
Back in the present, Hoover asks a succession of agents doing his dictation who the most important man of the 20th century was, and fires them when they get the wrong answer. Agent Smith is the first to go answering Joe McCarthy. “Joe McCarthy was an opportunist, not a believer,” Hoover says. Another agent answers Hoover himself, and Hoover responds by giving him a death glare. A third agent finally answers right by saying Charles Lindbergh (Josh Lucas).
The year is 1932. Lindbergh is internationally known for his flying. But he is about to be known for something else. The kidnapping of his son. Hoover and Tolson come to the Lindbergh home and see that evidence is being mishandled and contaminated by local police who think Hoover’s scientific theories are foolish. Hoover sees the ladder and sees it is cracked, deducing that the kidnapper fell with the baby in his arms. Hoover also sees the ransom note and notices several misspelled words, giving him a vital clue. After talking with Lindbergh briefly, Hoover and Tolson leave.
Hoover goes to a Senate hearing and asks that the Lindbergh law be passed. The law would make kidnapping a federal offense.
Hoover and his team take over the bureau smoking lounge and use it as their crime lab. They bring in a wood expert in order to find when and where the ladder was made so they can track the kidnapper.
However, Lindbergh still intends to pay the ransom, saying money matters nothing to him as long as he gets his son back. Hoover asks the bills be marked so they can be traced, and promises Lindbergh no actions will be done UNTIL his son is returned to him.
Lindbergh pays the ransom, and then finds out where his son is supposed to be, on a boat out at sea. Lindbergh flies out himself but there is no such boat. The kidnapper lied.
Back in the present, Hoover orders Tolson to do some wiretaps.
Back in 1932, Hoover has a meeting with President Roosevelt. He has a file with him. Hoover has dinner with Tolson and later reveals he showed FDR files that proved his wife was having a lesbian affair with a reporter. FDR gave Hoover more power in exchange for silence. The bureau is now the FBI or Federal Bureau of Investigation. Hoover wants Tolson to be his number two man. Tolson agrees as long as the two of them, no matter how good or bad the day is, have lunch and dinner together. Hoover smiles. “I wouldn’t have it any other way,” he says.
Two men are near the Lindbergh residence when one jumps out needing to take a piss. He finishes up only to find a skeleton. It is the body of Charles Lindbergh’s son. He died not far from his home.
Hoover relates his woes about how the investigation ended to his mother. Anne says they are all at fault for letting evil flourish until it attacked them all. Anne says the blood is on Hoover’s hands as well. “Yes, mother,” Hoover says.
Hoover attends a Senate hearing in which he requests more money. The lead senator attacks Hoover’s qualifications to lead, noting he has not made a personal arrest. Furthermore, the urban legend of him killing Dillinger is false; Melvin Purvis did. Hoover is stunned speechless.
An enraged Hoover tells Tolson to fire Purvis. Tolson tells him firing a national hero would be a PR disaster. Hoover says to demote him to a desk, keeping him out of the spotlight (Hoover felt small for never having any true glory himself). Hoover leaves Tolson behind despite their promise never to be apart for meals because he feels Tolson held back during the hearing.
Hoover starts to be more proactive, making several personal arrests so no one will question his character or qualifications as Bureau chief.
Hoover invites Tolson on vacation to the race tracks. Tolson agrees.
Hoover meets with the wood expert who explains he needs to contact every lumber mill in the country in order to find the correct swirl pattern of the wood in order to find out where the kidnapper bought it from.
Hoover narrates that as they continued to capture or kill the remaining Public Enemies, the public perception changed. Now people wanted to see movies about heroic cops. They want to be FBI agents, or G-men.
Hoover, Anne, and Tolson go to a movie premiere of a new police film. Afterwards, Tolson and Hoover hold hands in the car, something Anne sees.
Hoover and Tolson go to a restaurant where they share a table with some women. One of the women has an obvious attraction to Hoover, which makes him uncomfortable. She asks him to dance, and Hoover hastily makes an excuse about having much work to do the next morning. Hoover and Tolson leave.
Hoover is at home, stuttering over the stress of that incident. His mother Anne chides him, and tells him to practice his speech like the doctor told him to. Hoover eventually calms down and plainly states he doesn’t like to dance, especially with women.
Anne asks if he remembers a certain boy that Hoover knew when he grew up. That boy was nicknamed “Daffy” short for daffodil. He was caught cross dressing and forced to stand outside and have all the kids mock him. Six weeks later, the boy killed himself. “I’d rather have a dead son than a daffodil for a son,” Anne coldly states. “Yes, mother,” Hoover replies. Anne teaches Hoover to dance.
Hoover has a break in the Lindbergh case when some of the marked bills show up. All the people they interview give the same description. A gas station attendant even wrote the license plate down on his bill, giving Hoover a direct lead to the kidnapper.
The kidnapper, Bruno Hauptmann is stopped by a local cop for a broken tail light. Hoover busts in and arrests him for kidnapping and murder of Charles Lindbergh Jr.
Back in the present, we see why Hoover wanted wiretaps. He wanted leverage over Martin Luther King Jr. who he considered an enemy of the U.S. He listens to King have an affair when he gets a call from Helen. JFK has been assassinated. He immediately calls Robert Kennedy and tells him his brother has been shot in Dallas and hangs up the phone. Robert Kennedy screams into the phone in shock, having heard of the news from Hoover before his own family could tell him.
Hoover and Tolson go the racetrack. Later that night, Hoover admits how much he needs Tolson and Tolson says he loves him. Hoover asks about Tolson’s opinion on an actress and Tolson gives it.
Hoover reveals that he has been seeing her and intends to possibly marry her (so to keep his homosexuality a secret). Tolson is aghast and says he will not be humiliated. Hoover asks if Tolson wants him to be incomplete. Tolson starts smashing liquor bottles and says Hoover is a “scared, heartless, horrible little man!”
Hoover and Tolson beat each other up. Tolson kisses Hoover and Hoover tells him never to do that again. “I won’t,” Tolson coldly replies and gets up to leave.
Tolson warns Hoover that if he EVER mentions the woman again, he will cut himself out of Hoover’s life. Tolson leaves. “I love you Clyde,” Hoover says after he leaves.
Back in the present, Hoover intends to discredit King with an anonymous letter before he is to receive the Nobel Peace Prize. He makes a reluctant Helen write a letter posing as a member of the King entourage and releases the King sex tapes, hoping he will decline the award and fade to obscurity.
Back in the past, the trial of Bruno Hauptmann takes over, with Hoover getting the credit for bringing him to justice. The evidence is great against Hauptmann and he is found guilty and sentenced to death.
Back in the present, Hoover and Tolson go to the tracks where Tolson has a stroke. He lives, though will have his productivity cut down. When the doctor suggests that Hoover cut down his hours, Hoover threatens to blackball the doctor out of his profession if he ever insults him like that in front of his staff. The doctor apologizes and mentions vitamin shots to boost productivity. Hoover hires the doctor for daily visits.
Hoover and Tolson are watching the King ceremony, waiting for King to decline the award. To his shock, King accepts the award. Hoover’s plot failed. He shuts the television off angrily.
Back in the 1930s, Hoover’s mother dies. He cries at her death. Later that night, he puts on one of her dresses and a necklace, possibly finally accepting who he is. He hears his mother’s voice to be strong and collapses to the floor and cries.
We see a montage of images as Hoover narrates on how those who do not learn from history are doomed to repeat. We see footage of the Vietnam War and MLK Jr. being assassinated.
Nixon (Christopher Shyer) is sworn in as President. Hoover goes to see him with a file, obstinately to get more freedom for the FBI.
Helen comes in to his office and finds him crying. Hoover asks Helen to do something for him. If anything should happen to him, Nixon will come after him and crucify him and the FBI. He is afraid Nixon will find his “Private File” in which he kept dirt on everyone. Helen promises they will never find it. “Thank you Helen,” Hoover says with much affection (a telling scene as he always referred to her as Ms. Gandy).
Hoover asks if he kills everything he loves. Helen knows he is talking about Tolson and says he is still alive. Hoover asks about the bureau they built. Helen assures him that his legacy will be protected and she will never betray his secrets.
Hoover has dinner with Tolson. Tolson puts Hoover in his place. Tolson says he read Hoover’s biography and tells him most of it is fiction. Many of the arrests he claimed to make he didn’t. He didn’t arrest the Lindbergh kidnapper; he wasn’t even there. And Charles Lindbergh didn’t have faith in him; that day at the house Lindbergh refused to speak to him, calling Hoover a “fussy man.” Machine Gun Kelly didn’t say “Don’t Shoot!” when he was killed; Hoover made that up to sell comic books. Hoover has told so many exaggerations and lies that he doesn’t even know what the truth is anymore. Tolson says he can lie to himself and the world but he cannot lie to him.
Hoover tells him the day of their interview the real reason he was sweating because he realized in that moment how much he needed Tolson. Hoover kisses Tolson on the forehead in a rare moment of affection. “Thank You Edgar,” Tolson says. Hoover goes home, complaining of indigestion.
Helen comes in to work the next day, and gets a call from Hoover’s maid. Hoover died that night. Helen gets to work.
Nixon hears about Hoover dying and quickly gets his agents to Hoover’s office to locate the private file. “I want those fucking files,” Nixon sneers.
Nixon goes on television to tell the nation of the passing of Hoover, highlighting his years of service to the nation. Nixon’s men go to Hoover’s office but don’t find the files.
Helen already recovered them and in a final act of loyalty and love, shreds the private file at Hoover’s request, protecting his legacy.
Title cards state that little is known of Hoover’s private file as only fragments have been recovered.
Clyde Tolson inherited Hoover’s estate and accepted the flag at his funeral.
Tolson’s grave is not far from J. Edgar Hoover’s.