The underlying principle of how Activity was generated — Shen Cong was honest with himself that he didn't know.

His best working theory: the apocalyptic meteor shower had deposited vast quantities of meteorite fragments across the world. Those fragments emitted a catalytic radiation that triggered two distinct reactions in metal — activation and corrosion.

The activation side remained opaque to him.

The corrosion side, though, had observable mechanics. Metal exposed to meteorite fragment radiation underwent a corrosive reaction: mass decreased, Activity dissipated, and large quantities of heat were released in the process.

From that property, his mind jumped to a device for converting heat into kinetic energy — a steam engine.

Coal power, nuclear power — strip away the complexity and both were fundamentally the same thing: a machine for boiling water. Heat energy converted to steam, steam converted to mechanical work. If meteorite fragment radiation could make metal release heat continuously, then designing a water-boiling system around it should theoretically produce usable work. Possibly even a viable engine.

The principle was straightforward enough. Configure the meteorite fragment as a reactor core. Pack it with metal feedstock. Arrange a loop of hot-water pipes around the exterior. As the metal corroded and shed heat, the pipes absorbed it, fed it into a steam generator, a pressure cylinder performed work, and that work drove a generator — or turned an engine directly.

Simple in principle. Complicated in practice.

First problem: containing the meteorite fragment's radiation. Second: maintaining stable water circulation. Third: calculating how much corroding metal would be required to produce sufficient heat — too little and the water wouldn't reach boiling point, which would be embarrassing. When Shen Cong roughed out the full system design and tried to scale it to Great Vajra's power needs, the device came out roughly the size of two rooms.

"Not realistic for a vehicle. As a stationary power plant it might have legs, but onboard there are too many constraints."

He sketched a few diagrams, then set it aside.

He still had a second idea — cutting an Activity field.

As an autodidact who'd spent…