Upon Soil They Made is a record of the near future, describing a fledgling space-age humanity reaching out for the stars for the first time. Having dispersed through the Solar System, we search beyond the Sun for a planet we can call home. Via a groundbreaking interstellar mission, we send probes to land on and terraform several exoplanets, yielding new homes and interesting failures alike. However, one planet in particular is unusual: It is habitable, its land ready for settlement, but the probes that terraformed it are cut off from the outside world.

Left to their own devices, the probes begin to change. They improve and they mutate, reacting to challenges they were never designed for. A bedazzled humanity only watches as the altered machines become something else entirely. The planet has become home to a biosphere of creatures, a patchwork of countries, a phenomenon brand new to the Universe.