That night for the longest time I didn’t sleep. The skies grew clear overhead and stars dazzled down upon us as the temperature fell away. Each breath hurt, drawing frozen razors of air into my chest. Death seemed both near and inviting. I shivered despite the furs, despite layers and more layers. And when at last dreams took me down I held no surety of ever waking.

In some dead hour past midnight the silence woke me. The unrelenting wind had for once relented, dropping away to nothing. I cracked open an eye and stared into the darkness. The miracle came suddenly and without warning. In one moment the sky lit with shifting veils of light, rolling through the colours, first red, then an eerie green, next a blue I’d not seen before. And always shifting, from one serpentlike form to the next. The silence and the scale of it kept the breath in my chest. The whole sky overwritten, a hundred miles and more of the heavens dancing with glory to some tune that only angels hear.

I know now that it must have been a dream, but in that moment I believed it with all my heart, and it filled me with wonder and with fear. Nothing before or since has made me feel so small, and yet that great and dancing mystery of light, huger than mountains, played out above an empty wasteland to no audience but me . . . it made me feel, just for the briefest time . . . significant.

In the morning Fimm did not rise.

“Now it is my turn.” Fjórir sewed his brother into his sleeping sack with a long bone needle and gut thread.

“Will he rise?” I eyed the sack, half-expecting it to move.

Snorri shook his head, solemn. Behind him Tuttugu rubbed his eyes. Of all of us the quins, now quads, seemed least moved.

“He’s frozen,” Snorri said.

“But.” My face felt too solid for frowning. “But you found a dead man struggling after a day or more in a snowbank.”

“The necromancers inject them with an elixir. Something of oils and salts, the Broke-Oar said. It keeps them from locking solid.” Snorri had told me this before, but the cold had frozen my memory.

“This army beneath the ice . . . Olaaf Rikeson’s troops—the Dead King’s men—will need to thaw them and treat them in this manner. Unless they have some new magics it doesn’t seem possible. The effort involved to drag them frozen to the south, or to bear sufficient fuel north . . .” I thought of the other part to the tale Snorri had told. The key that would open the frost giants’ gates—Loki’s gift. The key that would open anything. “Perhaps all they ever wanted was Rikeson’s key. That one thing.” And for some reason that thought worried me more than an army of corpses rising from the ice.

• • •

Snorri had aimed west of the fort so that the line of the Bitter Ice could lead us east towards it. If he had steered us wrong, then we were walking away from the fort into the ice-bound wastelands of the interior, where we would all die without the least inconvenience to anyone. Death seemed certain either way, and if turning back alone offered even the slightest hope of survival, then I would have been off without delay. Unfortunately, as Tuttugu had discovered in battle, running away is sometimes the least safe option, and whilst dying was the last thing I wanted to do, dying by myself seemed somehow worse.

I staggered on, across the unending whiteness, wondering if the Silent Sister had already watched my suffering when she looked beyond tomorrow. I crunched the ice, feet numb, the wind’s keening filling my head. Had she counted out each frozen step or just seen the great white shape of our trek across the snows? How many possibilities had lain strewn across the future for her? And how many of them saw us dead? Foot before foot, too cold for shivering, dying by degrees. Perhaps in some futures the crack that chased me had caught and destroyed me before I even reached Snorri; in others he may have killed me as I ran into him. Did she know for certain that her spell would find a home in us, be carried north to the very edge of the Bitter Ice? Did she know whether her magics would wither inside us or take root and grow into more than they had been? Was she certain, or was she maybe, like her great-nephew, a gambler always ready to roll those dice one time too many? I saw her narrow smile in my mind’s eye, and it did little to warm me. Foot before foot. Endlessly on.

• • •

Just as Snorri had described, the Black Fort took me by surprise. The landscape offered no clues, no buildup, no growing promise of journey’s end. One moment it was a featureless white wasteland, bounded on one side by the Bitter Ice; the next moment it was the same featureless wasteland, except there was a feature, a black dot.

The trek had worn us to our final strength—Fimm it had worn past even that—but we were none of us the shambling, frostbitten wreck that Snorri had been when he had last stumbled to the gates. We came with at least some measure of fight in us, some final reserve to draw upon. And, as little as I wanted to battle anyone, I knew for sure that without the chance to rest and restock in the shelter offered by the Black Fort, I for one would not survive a return journey.