It was loosely based upon the 1943 science fiction short story "Mimsy Were the Borogoves" by Lewis Padgett (a pseudonym of husband-and-wife team Henry Kuttner and C. L. Moore).

The film features Timothy Hutton, Joely Richardson, Rainn Wilson, Kathryn Hahn, Michael Clarke Duncan, and introduces Rhiannon Leigh Wryn as seven-year-old Emma Wilder and Chris O’Neil as ten-year-old Noah.

A scientist in the distant future has set out to avert a catastrophic ecological disaster, and sends a small number of high tech devices that resemble toys back in time to modern day Seattle.

The children gain genius-level intellects and psionic powers: Noah can teleport objects using a card-sized rectangle of green lines of light and a conch shell to control spiders, but thanks to her link, Emma develops the more advanced abilities, becoming the only one who can use the "spinners", stones that can float and produce a force field.

The Last Mimzy is loosely based upon "Mimsy Were the Borogoves" by Lewis Padgett (the pen name of collaborators Henry Kuttner and C. L. Moore); the story appeared in John W. Campbell's magazine Astounding in 1943.

The story makes the point that exposure to novel concepts would alter the children's perceptions "naturally" (irrespective of any intention on the part of the device's creator), since it would take place during an early phase of their intellectual development.

Both the film's and short story's titles are derived from the third line of the nonsense verse poem "Jabberwocky" in Lewis Carroll's Through the Looking-Glass, and What Alice Found There.

[5] The Last Mimzy: Stories, a retitled repackaging of the collection The Best of Henry Kuttner, was released in paperback, with a new title and cover art to tie in with the film.

"I think together we've come up with a song that captures the themes of the movie—the clash between humanity's best and worst instincts, and how a child's innocence can win the day", Roger Waters commented.