The last man in Texas was a criminal many times over. He had refused all evacuation orders, built a compound in what had been a National Park, back when the temperatures allowed something worthy of the name to exist so close to the Equator, and hoarded water illegally for years. And those were only the ones he had committed under the Environmental Laws; he had had to break the law equally often, to get the riches to pay for his more recent crimes.
This made him Perez' business. The entirety of it, for if he was the last man in Texas, Perez was the last lawman of the Lone Star State, even if she was working from the hot but still habitable Austin-in-Exile, in South Canada. Perez would have a job to do for as long as the man kept himself in Texas, and although some people would have considered it a proper and good reason for both to reach an agreement, Perez wanted very badly to retire, for she had grown older than she had thought possible, and had still plans of her own. On the other hand, the prospect of going back to Texas didn't strike her as a great idea; she would need a military-grade support convoy to get through the superheated desert of the Scorched Belt, and going from what she had found about the guy, she would also need military-grade firepower to get to him once she arrived to the refrigerated tin can he called his ranch. He wouldn't be a threat, as such — hell, she could blast the bastard to pieces from where she stood just by filling the proper form — but that would have been passing the bucket.
The last outlaw in Texas, Perez felt, deserved another kind of deal.
So she called the guy, and watched and listened to him. He began right away by calling her a cunt, to which she responded by threatening to castrate him from orbit with a death ray. Not that she had that kind of budget, but it seemed to put them in what you'd call a conversational level field. Once half-assured that he was not in any immediate threat of invasion from a platoon of genetically modified UN green beret soldiers (funny how they could make even the regular stuff sound like a conspiracy), the guy felt relaxed enough to start talking about his plans. The man had plans out of his ass. He'd find water (because, you see, the NASA maps had been lying for decades, and he was sure there had to be water somewhere), and then he'd rebuild the soil. He didn't seem to have much of an idea about phosphorous budgets and heat-resistant microbial strain loads, but it was clear to Perez that he wasn't so much a rancher gone insane as just somebody insane with a good industrial-sized fridge to live in. By the time he was talking about getting "true Texans" to come back and repopulate, Perez felt she had learned enough about her quarry.
She told him she would help.He couldn't trust the latest maps, of course, which were all based on NASA surveys, so she offered to copy from museum archives everything she could find about 18th century Texas — all the forests, the rivers, and so on. She'd send him maps, drawings, descriptions, everything she could find.
He was cynically thankful, suspecting she'd send him nothing, or more government propaganda.
Perez sent him everything she could find, which was of course a lot. Enough maps, drawings, and words to see Texas as it had been. And then she waited.
He called her one night, visibly drunk, saying nothing. She put him on hold and went to take a bath.
Two days later she queried the latest satellite sweep, and found the image of a heat-bleached skeleton hanging from an ill-conceived balcony on an ill-conceived ranch.
So that's how the last outlaw in Texas got himself hanged, and how the last lawman could finally give up her star and move somewhere a little bit cooler than Southern Canada, where she fulfilled her long-considered plan and shot herself out of the same sense of guilt she had sown in the outlaw.