Running the whole way, eight hundred li at speed.

At nightfall Shen Cong reached Mount Tai at last, and the old lair he had built for himself. The Vajra Fortress came to rest, and leaning back in the driver's seat, Shen Cong felt his heart stir for no reason he could name.

The reason he had come back to Mount Tai was simple enough. He had felt that after fifty-six days of metallic gradation he had at last completed the Lv2 Pitch-Black Era's lymph-gold/gland-gold stage.

With that stage finished, the Pitch-Black Era was behind him, and he had formally entered the as-yet-unnamed Lv3 era.

"I ought to have begun the metallic gradation of nerve-gold by now." Shen Cong looked at his own hands, which had begun to tremble faintly, and felt some little unease.

The nerve-gold stage meant the metallic gradation of the nervous system.

By Nan Guohua's metal contamination model, the Lv2 Pitch-Black Era was a large-scale alteration of the body which would distort the sensory system and produce a pitch-black darkness in the perceptions, which was why it was called the Pitch-Black Era. Shen Cong had proved that the Pitch-Black Era was not black at all — perception grew sharper — though where food was concerned it was pitch-black enough.

Metallic gradation of the nervous system, however, would bring on far more complicated changes. The electric charges that carry signals through nerve cells, for example, might well short out once the cells metallized.

And that possibility had now become fact.

Shen Cong had come back to the lair precisely because he had felt his body beginning to show slight symptoms of paralysis — most obviously in his hands, where the sense of touch was keenest. The numbness had grown stronger and stronger over the drive, and by now he could feel a faint paralysis over his whole body.

"How is nerve-gold actually going to change me? If it really does short out and cost me the working use of my nervous system, will I end up paralyzed down one side?"

Until he understood these things, Shen Cong was…