He typed it all out in the research log, laying it end to end:

“Vajra’s metal frame carries Activity. The properties of Extension, Amalgamation, and Exchange all show an affinity for metal — fast Amalgamation on metal substrates, slow on non-metal. The Burrower, Gnawrat, and Fangwolf all carry Activity, with cores that show progressive metallic transformation in their bone structures. Bone contains calcium, sodium, magnesium, iron, and other metal elements — calcium being the most abundant. Metal elements are biologically essential in both animals and humans.

“Activity appears to exist in a form consistent with electromagnetic radiation, with possible radioactive properties. In nature, almost all radioactive elements are metals, with the exceptions of radon and astatine — and radon is a decay product of radium, itself radioactive metal, and ultimately decays to polonium, also a radioactive metal. Astatine has metallic properties and derives from the decay of francium, eventually decaying to lead…”

He read it back.

He’d gone in a complete circle. The first thing he’d ever concluded about Activity was that it was connected to metal. Everything since had added layers of detail, but the core insight hadn’t moved. The fundamental question — whether the meteor shower and the Activity were related, and if so how — remained completely open. The research had hit a wall it couldn’t see past.

He closed that line of thinking and turned back to the rabbit.

“Variable mutation profile confirmed, but Activity core location still unknown.”

That was the piece that nagged at him. He couldn’t find an Activity core in himself. Couldn’t find one in Vajra. Those two were the anomalies — every animal he’d studied so far had a clear core, the densest metallic structure in their body, where the Activity concentrated. He and Vajra didn’t seem to follow that pattern.

Humans were animals, biologically speaking. Big brains aside, the underlying machinery was the same. If mutated animals developed Activity cores, there was no obvious reason humans would be exempt. He might have one and simply not know how to locate it yet.

He briefly considered dissecting the rabbit to check its internal structures.

He put the thought away. Live specimens were too valuable to waste before they’d given up everything they had to give.

He typed a new entry:

Plastic Rabbit: mutated lagomorph. Mutation indicators minimal. Activity core: not yet identified. Confirmed omnivore; recorded consumption of plastic. Further observation ongoing.

Then he caged it and got back to Vajra.

Another week passed.

No storms. No dust. No attacks, no sightings. The world outside was quiet in a way that felt less like peace and more like held breath.

He ran his days on a tight schedule:

Six hours of sleep. Nine hours of Activity-guided repair work on Vajra. Three hours of radio study. Two hours of physical training and slingshot practice. Two hours of meals, novels, films. One hour patrolling the surrounding terrain. One hour observing the Plastic Rabbit.

The discipline held. It always had — six years of solo workshop life had built habits that the apocalypse hadn’t broken. Structure was how he stayed functional.

After ten days of sustained work, Vajra’s primary frame was fully restored. The exterior armor had its spikes back, the plating was true, the silhouette looked exactly like the vehicle that had left the warehouse two months ago — brutal and imposing and reassuring in the way that thirty tons of welded steel tended to be.

The interior was another matter. Electrical systems and electronic components were still mostly offline. Propulsion would take another four or five days at minimum.

The radar was back up, at least. The AN/PPS-15A turned steadily on the roof, sweeping the area. Shen Cong made several excursions wearing the Optimus 1.0, armed up, pushing as far as a kilometer out. He found nothing moving.

He left the three traps out at range, baited with the rotting Fangwolf meat. The meat was past the point of being food — he was feeding the edible cuts to the Plastic Rabbit and burying the worst of it — but rotten meat attracted scavengers, and scavengers were still potential meals and research subjects.

What he got instead was flies.

Green bottle flies, drawn to the bait, buzzing around the cage in loose orbits. Entirely ordinary. He caught several, ran the standard checks, and confirmed they had no Activity whatsoever. Just flies.

Which was, in its own way, informative.

Not everything mutated. Some things came through unchanged.

Then the obvious follow-up question presented itself.

What if I fed them Activity-rich meat? Could I induce the mutation?

He found the idea genuinely exciting in a way that surprised him slightly. He pulled out a piece of Gnawrat meat that was on the edge of turning — still had some Activity left in it, just barely — and dropped it into a mesh container with five green bottle flies.

Then he stepped back and waited approximately zero seconds before acknowledging that this was going to take a very long time to produce any visible result.

The Plastic Rabbit had been eating Activity-rich meat for a week. Its ambient Activity output had increased by a barely measurable amount. His own accumulation, and Vajra’s, moved at the same glacial pace. The Activity didn’t rush for anyone.

He noted the experiment in the log and left it in the corner.

July 22nd.

The apocalypse had started on May 18th. Two months and four days.

He ran a mental audit.

Vajra’s Activity saturation still hadn’t hit 100% — the last few percent of non-metal components were stubbornly resistant. His own reserves were building, but slowly, fed by the Exchange link and whatever Activity-rich meat he could source. He didn’t have a baseline to compare himself against — no other survivors to exchange information with, no reference points for whether his progress was fast or slow by any external standard.

He decided not to worry about it.

As a human being, his advantage over the mutated creatures wasn’t strength or size — it was intelligence. The Burrowers, Gnawrats, and Fangwolves had all been running on instinct, and instinct had gotten every single one of them killed. Whatever Activity comprehension they’d developed, it wasn’t guided. His was. That gap mattered more than the rate of accumulation.

Besides — he had Vajra.

None of the creatures he’d encountered so far, up to and including the possible prehistoric crocodile, had actually breached Vajra’s armor. They’d bent it, scratched it, soaked it, and rolled it around a flooded plain for half a night, but they hadn’t gotten through.

The crocodile did leave a shadow, though. One he couldn’t quite shake.

A normal crocodile, mutated, had become something large enough to bat a thirty-ton truck around like a rubber ball. The logic extended uncomfortably in other directions. An elephant weighed three to five tons at baseline. A mammoth could hit twelve. If an elephant somewhere had undergone the same scale of mutation a crocodile apparently had —

Elephants are in Yunnan and Southeast Asia. Anhui doesn’t have elephants.

There’s a cattle-farming region around Tongling. And a Northeast tiger breeding facility.

He was getting ahead of himself.

He pushed the thought aside, topped up the Plastic Rabbit’s food, checked on the flies, and made lunch. Gnawrat steak, pan-fried properly this time, with enough oil and patience to get the texture right. The meat was coarser than he would’ve preferred — something about the muscle fiber — but the flavor was decent. Reminded him vaguely of pork.

After lunch, a free hour. He put on music instead of a film and spread his Activity cores out on the floor in front of him.

Eleven Fangwolf fangs. Two Gnawrat incisors. One pair of Burrower mandibles.

The fang-knife incident had clarified something he’d been circling around for weeks: the Activity cores weren’t just structural features of the mutated creatures. They were leverage points. Concentrated Activity that could be redirected, channeled, used to enhance whatever they were embedded in.

The prehistoric crocodile had changed his threat assessment. He’d gone into the apocalypse confident in his firepower — slingshot, hand crossbow, composite bow, Type 64 replica, three high-pressure air rifles, improvised explosives on hand, and a full suite of close-combat tools. Against anything animal-sized, he’d been comfortable.

Against something that treated his truck as a chew toy, comfortable wasn’t the right word anymore.

The cores could fix that. He was going to upgrade his weapons.

He looked at what he had and started thinking about what he could build.

(End of Chapter 14)