Trama

An adult Frank Walker (George Clooney) tells an off-screen audience about his attendance at the 1964 New York World's Fair as a child.

In the flashback, Young Frank (Thomas Robinson) eagerly enters the Hall of Inventions carrying a very large Duffle bag containing his invention: a jet pack he made. Frank meets David Nix (Hugh Laurie), an official who is unimpressed with Frank's limited jet pack. Frank does draw the attention of a young girl named Athena (Raffey Cassidy). Seeing his potential, Athena gives Frank a pin embossed with a "T" symbol and telling him to follow her onto Walt Disney's "It's a Small World" attraction at the Fair's Pepsi-Cola Pavilion. Frank sneaks onto the ride, where his pin is scanned, and he is transported into a futuristic city known as Tomorrowland.

After a disorienting ride, Frank finds himself on a foggy platform, but sees a strange flying vehicle taking off nearby, with Athena waving to him. Frank attempts to follow but finds himself on the edge of a platform. Suddenly, construction robots arise, creating new structures, but knocking Frank down to a lower level. As his jet-pack clatters to the platform, a robot nearby suddenly grabs it. Frank fights to get back his invention, but he is surprised when the huge Automaton fixes it. He falls from a ledge, but straps on his jet pack and lands safely before Nix and Athena. Mr Nix seems mildly amused that Frank's invention can actually fly. Even so, Athena gives the young boy a reaffirming smile.

The narration then shifts to Casey Newton (Britt Robertson) in the present year, who sneaks into a decommissioned NASA launch pad in Cape Canaveral, where her father Eddie (Tim McGraw) is an engineer. She sabotages the machines that are dismantling the launch pad. When she returns home, her dad tells her 'The end' of the space shuttle's former launch site is inevitable. Casey still feels she's contributing something with trying to slow down the deconstruction.

Unseen by Casey, Athena sneaks another pin that is programmed to Casey's DNA into Casey's motorcycle helmet. Casey goes to school but becomes a bother in all her classes. Her teachers tell of nuclear annihilation, planetary meltdown, and governmental collapse, but Casey just wants to know one thing: "how can we fix it?" However, this question receives no answers.

Casey hears that NASA has brought in working equipment from Orlando to continue disassembling the platform. That night, Casey attempts to break into the NASA compound again but is arrested. At the police station, she discovers the pin among her personal items. Casey discovers that upon contact, the pin instantly shows her a view of Tomorrowland that only she can see.

Later on that evening, Casey sneaks out of the house, and bicycles to a large field. Touching the pin this time, she finds herself in the center of a dazzling futuristic city, with jet-packs and hover-trains. She also becomes enamored seeing a rocket launch station and follows a group of space travelers before the pin suddenly runs out of power, and she finds herself having wandered waist-deep into a lake.

Assisted by her brother Nate (Pierce Gagnon), Casey finds a Houston memorabilia store called "Blast from the Past" related to the pin. Strangely, they only have a street address, but don't list an email or phone number. Casey tells Nate to cover for her while she takes a bus to Houston to talk to the store owners. The next day, Athena sees Nate in front of their home who asks to see Casey. When Nate attempts to tell Athena that Casey is away, she claims he's lying, and asks where she "really" is.

Upon meeting the two owners, Hugo (Keegan-Michael Key) and Ursula (Kathryn Hahn), she is told that the pin supposedly was a key to showing a world created by some of the greatest geniuses in history, who called themselves Plus Ultra. Hugo and Ursula tell Casey that the pin's vision is an insight into a secret place built by all the scientists and artists, who actually wanted to change the world. A place free from politics & allowing the freedom to create anything that anyone could imagine. Casey is inquired about it, and when she reveals to know nothing else about it, they attack her.

Casey is saved when Athena appears, stopping the two in their tracks with a time-bomb (a device that stops time temporarily in a 15-foot radius). As the two get free, Casey and Athena fight them, with Athena pulling off Ursula's head, and Hugo being skewered. Hugo and Ursula are both revealed to be robots. The two girls escape as the robots' self-destruct, destroying the store.

Athena reveals that she is an Audio-Animatronic robot, and the one who gave Casey the pin, revealing that she needs her help to save Tomorrowland. After Casey and Athena steal a car, Athena reveals her purpose is to find and recruit people who fit the ideals of Tomorrowland.

Athena confirms that Tomorrowland is real & she needs help saving it as someone invented something that shouldn't have. Athena also says that only one man can get them back into Tomorrowland.

Back in Houston, Police are combing through the wreckage of the store, when a black van pulls up, and several people get out, led by a smiling man who calls himself Dave Clark (Matthew MacCaull). When one of the officers finds the charred remains of Ursula's head, Dave pulls out a device that disintegrates the nearby officers. Once they are done away with, he informs the other members of his party to contact Governor Nix.

Athena drives Casey to Frank's home in Pittsfield, New York and abandons her there. Casey realizes that Frank is the person who can take her to Tomorrowland. The now reclusive, cynical Frank declines Casey's request to take her to Tomorrowland, having been banished from it years ago. Frank pushes Casey away saying that the Tomorrowland she saw when she touched the pin doesn't exist. Casey notices a number of cables leading from the main house, and finds they are all attached to an array of antennas and satellite dishes.

Setting a nearby tractor on fire, Casey gets Frank to leave the house and get inside. Frank manages to put out the fire, but Casey refuses to let him back in until he takes her where she wants to go. Inside Frank's house, Casey finds a probability counter marking the end of the world. Frank warns her that the future is doomed, but she disagrees, thus lowering the counter's probability.

While Casey explores the technology inside the house, Frank re-enters the house through a secret tunnel just as robots disguised as United States Secret Service agents storm the house intending to kill them.

Before the attack, Frank explains to Casey that he invented a machine to see the future and the machine told him that the destruction of Tomorrowland was certain. This is why he was thrown out & all the doors back in, were locked. For a moment Casey disagrees with Frank & for a brief second sees a much more pleasant future, where Tomorrowland exists and thrives. Frank manages to grab some things and stuff them in a bag, before he and Casey get into a bathtub, which rockets them out of the house as the former inventor self-destructs his birthplace.

After evading the robots and they meet Athena in the woods outside Frank's house. Frank resents Athena for lying to him about her true nature, but reluctantly agrees to help them get to Tomorrowland. The trio uses a Teleportation machine that Frank invented, jumping to the Eiffel Tower in Paris. They enter a room with mannequins of Gustave Eiffel, Jules Verne, Nikola Tesla, and Thomas Edison. Frank explains that the four men were the founders of Plus Ultra, a group of inventors dedicated to finding other dreamers and inventors who shared the hope of shaping a better future, which eventually led them to discover a new dimension where Tomorrowland was founded.

The trio enter a steam-punk like rocket hidden called the Spectacle underneath the tower, which launches into outer space and back towards Earth, finally arriving at a now desolate Tomorrowland. Frank hands Athena a small device: a 1-kiloton bomb the size of a small ball, that she hides in a compartment inside herself. Frank claims they may need it for leverage.

There, they find Tomorrowland in a state of decay. David Nix, Tomorrowland's governor, greets them. Nix takes them to a building linked to a Tachyon machine designed by Frank himself that can show images from the past and future, where Casey learns that a worldwide catastrophe will happen in the near future, and because of that, Frank lost all hope and was banished from Tomorrowland.

Zeroing in on the NASA landing platform, Casey pushes into the future but is surprised when the image becomes fuzzy. Pushing forward, she sees fire and smoke. Going over the globe, she sees other things: cities being destroyed, tornadoes and freak thunderstorms, before seeing her family's home underwater.

Frank claims that what they see is said to be coming in a month's time or less. Casey is angered as to why Nix hasn't told anyone on Earth about what will happen, but Nix shows no reason to be concerned: what will happen will happen on Earth. The city will survive. When this prompts Casey to ask why Nix doesn't allow those on Earth to come to the city, he counters that there is too great of a risk for humans to destroy it, just like the Earth. Casey does not accept that the world is destined to end, and the future slightly changes as a result, a fact that Frank glimpses, but Nix ignores and orders them arrested instead.

As they await being sent back to Earth, Casey realizes that a side effect of utilizing Tachyons to obtain information about the future is that it introduces a back-feed into the time flow. Frank's antennas and dishes were grabbing feeds of what the device was broadcasting. But the machine isn't just predicting the future it is causing people to give in to these visions, and just accept what will happen It makes the future it shows all the more likely to occur, creating a self-fulfilling prophecy. Destroying the device could avert the apocalypse.

They confront David, who admits he tried to prevent the future by projecting such images to humanity as a warning. Instead, they embraced the apocalypse, refusing to act to make a better future for their world. Believing that humanity simply gave up, David has also given up and intends to allow the apocalypse to happen so that he can rebuild the world to his liking.

Nix opens a portal to a beach, inviting them to live out the last days there, but Frank refuses, seeing that Nix has simply given up on Earth and intends to allow the apocalypse to happen. A fight ensues and Frank tries to use a bomb to blow up the machine. Mistakenly, the bomb goes off outside the portal and the explosion pins Nix's leg under debris. Nix retrieves a plasma gun and aims at Frank. Athena, who was able to see it happening beforehand due to the Tachyons, jumps in front of him and is shot beyond repair; that activates her self-destruct sequence. In her last moments of consciousness, Athena instructs Frank to take her to the machine and reveals that she loved him. Her self-destruction takes down the machine and kills Nix as well.

The story returns to the present, Casey opens the portal near her home and invites her father and brother into Tomorrowland. Frank decides to reopen the recruitment program, turning on the pin-making machines, and building a number of new child-looking recruiters.

Frank and Casey's audience is revealed to be androids like Athena, who are entrusted with new pins and instructed to bring other "dreamers" to Tomorrowland. A number of people find the "T" pins. As they each touch them, we then see dozens of people popping up in the vast wheat field, eyes drawn towards the spires of Tomorrowland.