up to a rhythm, and then a rising, low hum. The cavern brightens suddenly as the blue pylons turn white and blaze brighter, as do the tired yellow lights that they followed down the mosaic tunnel. Nassun flinches even in the depths of the sapphire, and in half a breath Schaffa has grabbed her away from the vine. His hands shake as he holds her close, but he doesn’t say anything, his relief palpable as he lets Nassun flop against him. She’s suddenly so drained that only his grip holds her up.
And in the meantime, something is coming along the track.
It is a ghostly thing, iridescent beetle green, graceful and sleek and nearly silent as it emerges from somewhere behind the glass column. Nothing of it makes sense to Nassun’s eyes. The bulk of it is roughly teardrop-shaped, though its narrower, pointy end is asymmetrical, the tip curving high off the ground in a way that makes her think of a crow’s beak. It’s huge, easily the size of a house, and yet it floats a few inches above the track, unsupported. The substance of it is impossible to guess, though it seems to have … skin? Yes; up close, Nassun can see that the surface of the thing has the same finely wrinkled texture as thick, well-worked leather. Here and there on that skin she glimpses odd, irregular lumps, each perhaps the size of a fist; they seem to have no visible purpose.
It blurs and flickers, though, the thing. From solidity to translucence and back, just like an obelisk.
“Very good,” says Steel, who is suddenly in front of them and to one side of the thing.
Nassun is too drained to flinch, though she’s recovering. Schaffa’s hands tighten on her shoulders in reflex, then relax. Steel ignores them both. One of the stone eater’s hands is upraised toward the strange floating thing, like a proud artist displaying his latest creation. He says, “You gave the system rather more power than absolutely necessary. The overflow has gone into lighting, as you can see, and other systems such as environmental controls. Pointless, but I suppose it does no harm. They’ll run down again in a few months, without any source to provide additional power.”
Schaffa’s voice is very soft and cold. “This could have killed her.”
Steel is still smiling. Nassun finally begins to suspect that this is Steel’s attempt to mock a Guardian’s frequent smiles. “Yes, if she hadn’t used the obelisk.” There is nothing of apology in his tone. “Death is what usually happens when someone charges the system. Orogenes capable of channeling magic can survive it, however—as can Guardians, who usually can draw upon an outside source.”
Magic? Nassun thinks in fleeting confusion.
But Schaffa stiffens. Nassun is confused by his fury at first, and then she realizes: Ordinary Guardians, the uncontaminated kind, draw silver from the earth and put it into the vines. Guardians like Umber and Nida can probably do the same, though they would try only if it served Father Earth’s interests. But Schaffa, despite his corestone, cannot rely on the Earth’s silver, and cannot draw more of it at will. If Nassun was in danger from the vine, that was because of Schaffa’s inadequacy.
Or so Steel means to suggest. Nassun stares at him incredulously, then turns back to Schaffa. She’s getting some of her strength back already. “I knew I could do it,” she says. Schaffa is still glaring at Steel. Nassun balls up her fists in his shirt and tugs to make him look at her. He blinks and does so, in surprise. “I knew! And I wouldn’t have let you do the vines, Schaffa. It’s because of me that—”
She falters then, her throat closing with impending tears. Some of this is just nerves and exhaustion. Much of it, though, is the sense of guilt that has been lurking and growing within her for months, only now spilling out because she’s too tired to keep it in. It’s her fault that Schaffa has lost everything: Found Moon, the children he cared for, the companionship of his fellow Guardians, the reliable power that should have come from his corestone, even peaceful sleep at night. She’s why he’s down here in the dust of a dead city, and why they’re about to entrust themselves to machinery older than Sanze and maybe the whole Stillness, to go to an impossible place and do an impossible thing.
Schaffa sees all this instantly, with the skill of a longtime caretaker of children. The frown