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.

"[1][2] Of the "dreamy, beloved" ongoing series,[3]The Film Stage noted, "Hertzfeldt has crafted what might be the crowning achievement of modern science fiction.

"[4] 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.

"[5] Still, aspects of science fiction appeared in his film It's Such a Beautiful Day and his graphic novel The End Of The World.

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 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."

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.

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.

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.

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.

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.

Cleaners ensure that timelines are properly maintained but they are also rumored to perform duties for more sinister purposes, notably secret assassinations.

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.

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 unusual hairstyle resembles the man who intentionally transported himself to "nowhere" in the second Episode, suggesting they are the same person).

David Prime reinstalls the ability to walk and reaches the Zorgbot, but upon trying to activate it, he finds it is out of order from all the years of inactivity.

124 years later, a now very elderly David Prime living on Earth is shopping on the Internet when he discovers that Zorgbots have just been invented.

The second-generation clone of David is gradually educated in his youth through a cognitive examination program titled "Godbaby" and as he ages, he remembers the efforts of his lineage.

By scanning the contents of the Zorgbot, David 2 is then able to locate Emily 9 on the mining planet, from when she recorded her message to his predecessor.

World of Tomorrow was released on-demand on Vimeo in March 2015, simultaneously with its continuing theatrical run in film festivals.

World of Tomorrow Episode Two: The Burden of Other People's Thoughts premiered in 2017 and received rare "A+" reviews from Indiewire and Collider, where it was described as "another soulful sci-fi masterpiece.

[15] World of Tomorrow Episode Three: The Absent Destinations of David Prime was released on-demand worldwide on October 9, 2020.

[16][17] Of the "dreamy, beloved" ongoing series, The Film Stage wrote, "Hertzfeldt has crafted what might be the crowning achievement of modern science fiction.

[25] In March 2021, Don gave an update during an interview with Gizmodo, estimating it would be "another couple years" until the release of Episode Four if he didn't reach a deal with a streaming service.

The first film won 42 awards, including: In December 2015, Hertzfeldt received a special award from the Austin Film Critics Association, "in celebration of a career of remarkable short filmmaking and contributions to animation spanning two decades, with the 2015 award-winning "World of Tomorrow" being recognized as his best work to date.