2015 American animated short film
World of Tomorrow is a series of animated science fiction short films written, directed, produced, animated, and edited by Don Hertzfeldt.
The series began with "World of Tomorrow" (2015), followed by "World of Tomorrow Episode Two: The Burden of Other People's Thoughts" (2017) and "World of Tomorrow Episode Three: The Absent Destinations of David Prime" (2020). 
The first film was nominated for Best Animated Short Film at the 2015 Academy Awards. 
All three films feature the voice of Julia Pott, frequently alongside Hertzfeldt's four-year-old niece Winona Mae, who was recorded while drawing and playing. Her spontaneous, natural vocal reactions and questions were then edited into the stories to create her character.
"Indiewire" called the first film "one of the greatest short films in the history of movies," and "Rolling Stone" ranked "World of Tomorrow" #10 on its list of the "Greatest Animated Movies Ever."
Of the "dreamy, beloved" ongoing series,"The Film Stage" noted, "Hertzfeldt has crafted what might be the crowning achievement of modern science fiction."
Development.
Hertzfeldt had long been interested in science fiction but hesitated to make a film set in a genre partly due to not wanting to be confined by it, noting, "it always seems to mean having to tread at least a little bit through overly familiar waters." Still, aspects of science fiction appeared in his film "It's Such a Beautiful Day" and his graphic novel "The End Of The World". He felt that the science fiction genre would specially make sense for his first foray into digital animation.
The design of the film was influenced by science fiction novels and magazine covers of the 1950s and 60s, and by Hertzfeldt wanting the film to have a storybook aesthetic. He worked on the first film simultaneously with his couch gag guest appearance on "The Simpsons". Both projects were the first time he had used digital animation in his work. Hertzfeldt was also responsible for the film's sound design and visual effects.
Plot.
"World of Tomorrow" (2015).
A young girl, Emily is contacted by a clone of her future self from 227 years in the future, created as a means of achieving immortality. They then travel to the clone's time and visit the Outernet, a future version of the Internet, where they explore memories of the clone's life.
The first memory is one from the clone Emily's childhood, where a male clone without a brain, nicknamed "David", is kept in stasis. Emily visits him until his death at age 72. Other memories the pair involve various jobs and loves of Emily's both on the moon and in outer space. Upon her return to Earth, the clone Emily opened an art gallery exhibiting anonymous memories. Here she meets a descendant clone of David, which ends prematurely with his own death, thus ending his family life.
Last, clone Emily reveals that in sixty days, Earth will be destroyed by a meteoroid. She reveals the true reason that she contacted Emily Prime: to retrieve an important memory from her original source before her own death, that of the original Emily and her mother walking together, which the clone had forgotten. The specific memory will comfort her in the days leading to Earth's destruction. Emily Prime returns home.
Episode Two: "The Burden of Other People's Thoughts" (2017).
Emily Prime is busy drawing in a white room when she is interrupted by a time-traveling visitor; a sixth back-up copy of the adult third-generation clone who contacted Emily Prime in the previous episode, known as Emily 6 (voiced by Pott). This back-up Emily has difficulty controlling her emotions and was next in line to be a proper clone of Emily, but believes she lost her identity, and decided to replace her mind with a copy of Emily Prime's mind using a partially broken neural network on Emily 6's time machine.
The two then start to merge their consciousnesses; inside Emily 6's mind, Emily Prime meets a younger version of Emily 6, and they explore a cave and talk about Emily 6's bracelet, a birthday gift from her sister Felicia. The younger Emily 6 falls asleep, and Emily Prime is transported back to the adult Emily 6 in a location in the sub-consciousness called the "Bog of realism". In the bog waters, Emily 6 buried many "glimmers of hope" from her youth that she could not fulfill when she became an adult; one of the glimmers Emily Prime picks up is a dream of becoming a dancer in "The Nutcracker" ballet.
The two stumble upon a large cloud that rains memories into a "Valley of Buried Memories" below, and explore it. The memories can be tasted to reveal what they contain, with many of them having been inherited from other Emilys. Emily Prime finds a memory of a younger Emily 6 in a large tube with other numbered back-ups, all of whose eyes are closed except for Emily 6. Emily 6 finds a memory that has not happened to either of them yet, and tells Emily Prime not to think of a "baby dinosaur" later. Emily Prime then views three memories of her life where she is unexpectedly visited by Emily 6, and the fourth and seventh back-ups of Emily as they intrusively tour memories of Emily Prime's life to reminisce. Emily 6 finds a memory that transports them to a moment where her younger self kills an insect, describing it as the saddest day of her life and lecturing about the equality of souls before declaring that "clones are better".
Emily Prime spots the stasis tube containing the unconscious body of Felicia floating around a red planet in space. Emily 6 reveals that Felicia is the fifth back-up, Emily 5, having been separated from Emily 6 following Earth's destruction and reprogrammed to store the memories of a deceased wealthy family. They were best friends who both did not want to be named Emily, so they agreed to call Emily 5 "Felicia" and traded their bracelets, revealed to be identification tags, causing the numbers "5" and "6" on their foreheads to be switched. Emily 6 has since been searching for Emily 5 but does not remember the planet she is located at, causing her body to physically distort from thinking about it.
Emily 6's mind breaks down further, believing Emily Prime to be Felicia, and she talks about living on the red planet together. Emily tells Emily 6 to close her eyes. Emily 6 tells a story about a memory of an unknown man who was accidentally transported by one of the Outernet's time-traveling units to "nowhere." They are next transported into the "logic center" in Emily 6's brain, who urges them to escape as soon as possible as any illogical thought could damage her brain. Emily Prime thinks of a "baby dinosaur," and the system promptly collapses, shutting off Emily 6's mind.
The two are then transported into Emily Prime's mind, where Emily 6 begins to disappear, as the neural network finishes its job of replacing Emily 6's mind with a copy of Emily Prime's mind. To console Emily 6, Emily Prime gives her a ticket to "The Nutcracker" as a present, and Emily 6 dances to the suite as she contemplates her death. Emily 6 gives Emily Prime her bracelet, telling her to give it to Felicia when they meet again in 230 years, and asks Emily Prime to tell her a story. Emily Prime tells a brief story of a superhero with untapped powers who will save everyone from monsters, before Emily 6 fades from existence.
Emily Prime then returns to her room, with Emily 6 now having the same mind as Emily Prime, and gives her bracelet back to her, declaring herself to be her new sister. Suddenly, the fourth and seventh back-ups of Emily appear, telling Emily 6 that she "can't live in the past and all that" and she says goodbye to Emily Prime.
Episode Three: "The Absent Destinations of David Prime" (2020).
The ninth back-up of Emily, called Emily 9 (voiced by Pott), arrives from the future into the room of an infant named David (voiced by Jack Parrett), and records and implants a short transmission and a larger compressed file into his brain that will become activated when he is older. Years later, the adult David is floating in a rocket in space when the hidden memory reveals itself. Emily 9 explains to him that, as seen in the first Episode, a future clone of himself will marry a future clone of Emily, die suddenly, and have his memories harvested by Emily. This means David is the original, the "David Prime". Emily 9 believes that she is the only clone of Emily to have inherited those memories from her. She tells him there is something important that Emily never knew and tells them she has hidden these memories for him to recover.
The neural implant technology in David's brain is unable to fully unpack this message from the future, as it takes too much storage space. He resorts to deleting many skills in order to make enough space to access the information. The transmission from Emily 9 provides David Prime with the coordinates he needs to travel to an abandoned mining planet where she has hidden his memories.
Upon arrival, she explains further that he will need to walk for about a day across the planet to find an additional package with directions. The further David Prime walks and listens to directions from the transmissions however, the more skills and basic human functions he is forced to delete due to limited storage space, causing him to deteriorate mentally and physically. Along the way, he discovers many scattered corpses of what appears to be himself, which Emily 9 explains may be distant clones of himself from unknown future timelines who may have inherited dim memories of being on the planet, and tried and failed to make the trip themselves to her package. A homing beacon activates in David Prime's brain. It creates an arrow guiding him to the nearby package, which Emily 9 says will ensure that only him, the correct David, will know where to go. Towards the end of his trek, David Prime is forced to delete his ability to walk and he drags himself across the planet's rocky surface to finally reach the package. He also becomes poisoned by alien cave worms, which causes his tongue to fall out.
The hidden package contains another transmission from Emily 9 where she explains that in 72 years from his time, cloning will become commercially available, with two emergency back-up copies normally being created alongside one main clone. After the invention of time travel, the fourth back-up copy of David, David 4, will be employed as a secret agent called a "cleaner" who will have the special ability to freely work and travel in a shadow realm in-between individual points of time. Cleaners ensure that timelines are properly maintained but they are also rumored to perform duties for more sinister purposes, notably secret assassinations. She then explains that David 4 will abandon his co-workers while performing a job in-between time, and become obsessed when he sees Emily for the first time, in love with another clone of David. David 4 plans to secretly assassinate this David and take his place in his timeline, so he can live the rest of his life with Emily.
The only reason why his plan is known in the first place is because his roommate, the third-generation clone of David he was based on, read his diary where David 4's plan is fully spelled out after he'd disappeared the night before. The third-generation clone of David tries to create his own in-between time travel technology to directly confront David 4 before the plan can be carried out, but his experiments fail. He instead places himself in a stasis tube for upwards of a century in the hopes that technology will have publicly advanced enough for him to find a way then to stop the assassination. However, his time in the stasis tube causes him to mentally deteriorate. He seems to lose his mind and grows his hair into an unusual style. He places a younger clone of himself in a stasis tube as a museum exhibit titled "Time is a Prison of Living Things", originally featured in the first episode. This third-generation David eventually disappears from the public record (his