Working on behalf of corporate interests, scientist Jonathan Meridith has created a miniature version of a remote planet (in the titular Wolf 359 system) in his laboratory.
Due to the miniaturization, this artificial world knows an accelerated development, thus allowing Meridith to study its evolution through an electronic microscope, and to observe the birth of archaic life forms on its surface.
Manifesting by night in the absence of light, the creature takes a physical shape into the laboratory itself, destroying all life inside it, including plants, a colony of ants and a couple of guinea pigs.
As the evolution of the miniature world progresses, Meridith observes a reproduction of the darkest moments of Earth's history at its surface (including the development of nuclear weapons).
There is a theory that Earth and sun and galaxy and all the known universes are only a dust mote on some policeman's uniform in some gigantic superworld.