Incandescence

Zak hadn't taken the light machine, because of its weight, but they had never imagined that such a device would be available. Ruz had made three clocks that could easily be read by touch, and Zak had practiced in total darkness setting up the most important instrument, the one that would allow him to measure the passage of an object across his field of view. Once that was in place, then so long as there was a beacon worth aiming at, he only had to be able to time the moments when it passed behind a series of metal wires. However dim or bright an object might be, whatever the color of its light, you always knew when it passed behind metal.

"An arc of light?" Roi said. "Do you know what that could be?"

"No," Ruz replied. "But be patient. We'll have the whole journey back in which to interrogate him. In fact, we should extract every detail and write it all down, so if the Splinter sinks back into the Incandescence and never leaves it again, we'll have a record of what lies beyond."

Roi struggled to imagine what it could be like, looking out into the void. "If the Splinter really did break in two, long ago, do you think we could ever find the other half? Ever see it, even if we couldn't reach it?"

Ruz pondered the question. "It's hard to know how far away its orbit might be. Until we know, in spans, how far away the Hub is, it's difficult to quantify anything else. At the moment, we're not even sure that our orbit is 'size eight', let alone what that would mean in terms of actual distances." He paused, then called out, "One-quarter of the dark phase remaining! Zak, you need to move now!" It had taken Zak almost a quarter-phase to ascend through the crack, and though it would be easier coming down they needed to keep a healthy margin of safety.

Roi waited for his reluctant assent.

There was nothing.

"Zak?" She pressed her body against the rock, straining to hear anything, a word or a footstep. "Zak?"

She climbed up into the mouth of the crack. "I'm going up there. Something's happened to him, I need to bring him back."

Ruz said, "If the void's harmed him, it will do the same to you."

"You know what his health is like! He's been sick even back at the Null Line. The effort of the climb would have been enough to weaken him."

"When we planned this trip," Ruz insisted, "we all agreed that only Zak would take the risk—"

Roi seethed with frustration. He was right, they had agreed, but she didn't care. She said, "I'm not going to waste time arguing."

She clambered up the inside of the crack as quickly as she could, forcing herself to ignore the instinctive urge to feel her way slowly through the darkness. The rock was sharp in places, and slippery with weeds, but she kept her footing, and kept advancing. She didn't try to judge the distance or the passage of time, she just willed herself forward.

When a hint of light appeared ahead, she made no effort to make sense of it. Moments later, she tumbled on to the surface of the Splinter.

A band of light was wrapped across the blackness of the void, an arc that stretched from a point high above the rock and swept around a quarter-circle before the Splinter interrupted it. The color of the light varied smoothly across the band from inner to outer rim; within it, small points of brightness slowly drifted, changing color as they moved. Roi looked away; the spectacle was baffling and hypnotic, but this was not the time to sink into the morass of questions that it posed. The illumination it cast on the rock around her was weak and shallow, barely more than that cast by the light machine, but she had no trouble spotting Zak.

She ran to him, and drummed directly on his body. "What happened? Can you move?"

He stirred feebly, but there was no reply.

"Climb on to my back. Can you do that?" She placed herself beside him and flattened herself against the rock.

Nothing. She waited a few heartbeats, but he didn't move.

"All right. I'm going to try to lift you. Relax your grip on the rock." She nudged his body and it shifted slightly; whether he'd heard her and complied, or had simply lost his hold along with his strength, he wasn't sticking.

Roi tilted her carapace and managed to get all four claws on her right side beneath him. The edge of her body was too blunt simply to slide under him, so she tried to raise him with her claws first. She was not so old and weak that his weight should be immovable, and she was sure that once she got him on to her back she would be able to move quickly enough.

She strained against the rock. The very posture that she was forced to adopt undermined her strength, but if she couldn't raise him she could at least make it easier for Zak to complete the action by his own efforts.

She kept pushing, clinging to the hope that in a few more heartbeats the balance of forces would shift, he would slide into place, and they would dash to safety together, but whether or not Zak was striving to assist her, between the two of them he was barely moving.