Mard withdrew his hand from the stone and made it clench into a fist, then opened it again. So there was the answer. “No sensation, though,” he insisted. “Just tingling.”

“Tingling is a sensation,” Querc pointed out.

Some hours passed. Prim, having nothing to do at the moment, found a hollow in the rock where she could curl up and pull her cloak up over her head to block most of the light from the sword. This flared and flashed unpredictably as Burr wielded it against the Cube. Edda had boosted him onto its flat top. He was carving off bits under the direction of Mab, who seemed to have a very clear notion of where it was and was not safe to remove material. From time to time a chunk of adamant would break free, slide off, and bang into the ground, startling Prim. So this was far from the most restful nap she had ever taken.

She must, against all odds, have gone to sleep, though, because at some point she woke up. A deep boom, transmitted through the bedrock of the Knot, had been felt in her ribs and was already just a memory. It was not accompanied by a crash of severed stone from the nearby Cube. This had nothing to do with that. It was bigger, from farther away. Yesterday she might have identified it as a thunderclap. Indeed they were still within the Evertempest, the entire purpose of which was to protect this place. But this didn’t rumble and reverberate like thunder. And no sound was reaching her ears. She peeled the hood back from her head and squinted in the light as chill dry air bathed her face. The others were still at work, much as before. The shoulders and sides of the Cube had been cut down quite a bit; Burr was now standing on a pedestal just wide enough to support him. Around that the stone sloped roughly down where he had chopped it away, and the crisp base of the Cube was obscured by shards that had sloughed off. Prim shaded her eyes with one hand and lay still for a while, maintaining firm contact between her body and the living rock of the Knot. Then she felt another of those shocks. She took her hand from her eyes, raised her head, and looked at the others. None of them seemed to have noticed. Burr and Mab were intent upon their work, as Querc and Mard were upon theirs.

Where was Edda? Prim stood up, more than a little stiff, and found the giantess off to one side, sitting on a natural bench in the rock. She was leaning a little to one side, gazing down as if the stone were a window, resting the palm of one hand upon it like a mother checking the pulse of a child’s heart.

So Prim wasn’t just imagining things. Which did not answer the question of what was shaking the foundations of the Knot so.