Summary: An adult Frank Walker talks to an unseen group about the future, beginning with his visit to the
1964 New York World's Fair as a child. In a flashback, he meets David Nix, an official who is unimpressed with Frank's prototype personal jet pack. Frank does draw the attention of a young girl named Athena. Athena gives Frank a pin embossed with a "T" symbol and tells him to follow her aboard the "
It's a Small World" attraction. Frank sneaks onto the ride, where his pin transports him to a futuristic cityscape known as Tomorrowland. Frank then passes the narration to teenager Casey Newton, from whose point of view the majority of the story proceeds, starting in more current time.
Casey is seen sneaking into a decommissioned NASA launch pad in Florida, where her father Eddie is an engineer. She sabotages the cranes dismantling the pad and returns home, where Athena, who hasn't aged since 1964, sneaks a "T" pin into Casey's belongings. The next night, Casey returns to the pad, but is arrested. At the police station, she sees the pin among her personal items, and discovers that upon contact, the pin instantly shows her a view of Tomorrowland. She briefly explores the vision until the pin's battery runs out.
Assisted by her brother Nate, Casey finds and visits a Houston memorabilia store related to the pin. The store's owners, Hugo and Ursula, question where she got the pin, then attack her when she says she knows nothing else. Athena bursts in and fights Hugo and Ursula, who are revealed to be
Audio-Animatronic (AA) robots. The girls escape as the severly damaged AA robots self-destruct. After stealing a car, Athena reveals that she is an AA robot, and the one who gave Casey the pin, stating that she needs Casey's help to save the world. Athena drives Casey to Frank's home in
Pittsfield, New York and leaves her there.
The reclusive Frank declines Casey's request for an audience, but she manages to lure him out of the house and sneak in, locking him out. Frank re-enters through a tunnel and tells her angrily that he was thrown out of Tomorrowland and cannot go back. He also asks if she would like to know the exact moment of her death. Casey ponders whether accepting the truth about her time of death would actually be the cause of it, preferring to make her own destiny. When she says this, a monitor showing the probability of the end of the world changes from 100% to 99.9994%, startling Frank. AA robot agents appear, ordering Frank to turn over Casey or be killed.
After evading the AAs and reuniting with Athena, the trio uses a machine that Frank invented to teleport to the Eiffel Tower. They enter a room with mannequins of
Gustave Eiffel,
Jules Verne,
Nikola Tesla, and
Thomas Edison. Frank explains that the four men were founders of
Plus Ultra in the 19th century, 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 they founded Tomorrowland. The trio enter a rocket hidden underneath the tower, which launches into space and travels to another dimension, arriving at a now-desolate Tomorrowland. Nix greets them and takes them to a building linked to a
tachyon machine designed by Frank that can show images from the past and future. Casey learns that a worldwide catastrophe will soon happen in her time. Casey does not accept that the world is destined to end, again causing the outlook to flicker, though Nix ignores it and orders them arrested.
Casey realizes that the tachyon machine is telling humanity that the world is coming to an end, causing a
self-fulfilling prophecy. Nix prefers to interpret it as the device effectively warned humanity, who didn't bother making an effort to save themselves. Nix opens a return portal to an uninhabited tropical island, where Frank and Casey can live out the last few days of the world. Frank finally refuses to believe that things can't change and fights Nix, sending Casey and Athena to use a bomb to blow up the machine. The bomb is accidentally thrown through the portal to the uninhabited island, with the explosion pinning Nix's leg under debris in Tomorrowland. When Nix retrieves a plasma gun and aims at Frank, Athena jumps in front of him and is damaged beyond repair, which activates her self-destruct sequence. In her last moments of consciousness, Athena instructs Frank to use her imminent explosion to destroy the machine, then reveals that she had grown beyond her programming and fallen in love with him. Her explosion destroys the machine and kills Nix.
Back in the present, Frank and Casey are revealed to be in Tomorrowland, with Casey's father and brother. Their audience is a group of AAs like Athena, who are given new "T" pins and instructed to bring other dreamers to Tomorrowland in order to save the world.
