There were plenty of those homeless, nameless transients in the world back then. The Comeback was just beginning to die out: a series of natural disasters that had devastated Earth’s population, tailed by decades of hyper-accelerated plant growth. People went to sleep in their normal beds and, overnight, found their walls and mattresses invaded by plants. And that was only if they were lucky—if they had beds left at all, after the relentless barrage of tsunamis and earthquakes and volcanic eruptions that had wiped out half of the world’s cities.

But everyone agreed that the plants were the worst part. There was no way to fight them; how could anyone battle the encroachment of something that swallowed human structures so utterly? How could they fight against the planet itself? Bombs did nothing; bullets were wasted on targets that threaded through the very floorboards. Any chemicals that might have been effective at beating back the invasion would have also killed or sickened any humans in the area. There was no winning that war. Maybe if they had had time to prepare, some kind of warning—but everything had fallen apart so fast.

Pundits claimed that the phenomenon was Earth’s retaliation against millennia of human pollution: the planet’s immunoreaction to heightened levels of carbon dioxide. A cleansing event. The system purging itself of the diseases that were killing it. The plants soaked up and converted the dangerous levels of CO2 in the atmosphere—but they also happened to subsume the very structures that had created that CO2 in the first place. It was, the pundits said, the era of humanity’s reckoning. Earth’s Comeback.

Hence the aimless wanderers, the refugees, the people raised to adulthood in the wild. There were biodome cities, of course, which offered some protection against the colonizing plants—but they never had enough room, or otherwise people didn’t have enough money to make it in.

And then there were the budding colonies in space, providentially placed by the Interstellar Frontier mere years before the Comeback hit. Most people fled to the sanctuaries on Phobos and Mars; there was plenty of room there. The only catch was affording it, and if you couldn’t afford it, you had to contract yourself to a lifetime of employment to the ISF. A rite of conscription, it was called. A lifetime of obeying their every command. But it was, people claimed, a small price to pay considering the devastation that awaited them back on Earth. They shed and discarded their old planet like it was yesterday’s damp coat.