The title of the original short story quotes a verse from "Jabberwocky", a poem found in the novel Through the Looking-Glass by author Lewis Carroll.
Millions of years in the distant future, a posthuman scientist is attempting to build a time machine and tests it by sending a box with a hastily gathered batch of educational toys into the ancient past.
The toys include a small transparent cube that both follows and interacts with the holder's thoughts, a wire maze puzzle employing a fourth dimension, and a detailed anatomical doll that possesses modified versions of human organs, plus unknown additional structures.
In its words, they identified the time-space equation that guided their production, organization, and operation of the abstract machine; the title of the short story is a line from the poem.
One day, their father hears the children's cries of excitement from upstairs in their house and he arrives in the doorway of Scott's bedroom, just in time to see his young son and daughter vanish in a direction he cannot comprehend.