The girl is crossing a frontier that exists only in databases. Her phone whispers frantically on her ear: crossing such a frontier triggers no low-priority notification, but the digital panic merited by a lethal navigational mishap. Cross a line between two indistinguishable plots of land and you become the legitimate target of automated guns, or an illegal person to be sent to a private working prison, or any number of other fates perhaps but not certainly worse than what you were leaving behind.
The frontier the girl is crossing separates a water-poor region from a barren desert, the invisible line a temporary marker of the ever-faster retreat of agricultural mankind. The region reacts to unwanted strangers with less robots but as much heavily armed dedication as any of the richer ones. But the girl is walking into the desert, and there are no defensive systems on her way. There is just the dead sand.
She doesn't carry enough water or food to get her to the other side.
* * *
The girl went to a hidden net site a friend had shared with her with the electronic whispers and half-incredulous sniggers other generations had reserved for the mysteries of sex. Sex wasn't much of a mystery to their generation, who had seen everything long before it could be understood with anything except her mind. But they had never been in a forest, and almost none of them ever would. They traded pictures and descriptions of how the desert looked before it was a desert, and tried to imagine the smell of a thousand acres of shadowed damp earth. It was a fad, for most. A phase. Youth and nostalgia are mutually incompatible states.
Yet for some their dreams of forests endured: they had uncovered something, a secret, found because they weren't welcomed into the important matters reserved for grownups. Inside the long abandoned monitoring network their parents' generation had used to attempt to manage the retreating forest, some of the sensors were still alive. Most of them were repeating a monotonous prayer of heat and sand to creators too ashamed of their failure to let themselves look back.
But some of the sensors chanted of water, and shadow, and biomass. The girl had seen the data in her phone, and half-felt a breeze of leaves and bark. What if satellite pictures showed a canyon that, yes, could be safe from the soil-stealing wind, but was as barren as everything else? What of that?
The girl thought of her parents, and of the child she had promised herself she wouldn't give to the barren earth, and with guilt that didn't slow her down, she took the least amount of water she thought would be enough to get her to the canyon, and went into the desert.
The dull sleepless intelligences inside the border cameras saw her leave, but would only alert a human if they saw her walking back.
* * *
The girl will barely reach the canyon, half-dying, clinging to her last bit of water as a talisman. There will be no forest there, nothing in the canyon but dry sand. But in the small caves between the rocks, where the geometry of stones has built small enclosed worlds of darkness, she'll find ugly, malevolently tenacious, and very much alive mushrooms, and around them the clothes of those who will have reached the canyon before her. Most of their clothes will be of her size.
The girl will understand. She won't drink the last of her water, but give it to the mushrooms. Then she will lie down and close her eyes, and fall sleep in the shadow, surrounded by a forest at last.