‘Be careful, Yanny,’ says Zara, and she sounds as afraid for him as I feel. He’s just a slight, bright thing against so much darkness.

He winks, and the shadows come between us, and I put my fingers on to the acorn at my neck, just to check, and there it is, shining at me through a sudden opening in the trees – a swathe of ice as barren as my father’s heart.

I stumble on the wiry roots and slam my way through the bracken, fighting as much as running, fending off the brittle twigs that claw at my clothes, Zara by my side.

How could we leave him on his own?

I keep twisting through the trees, knowing that if I stop for even an instant, I’m going to turn back around and tell him we were wrong, there’s nothing we can do better than fight by his side. But the way gets colder as we go, and I know we’re getting closer to what Nan and I sought, so many times, except we never got this far. We didn’t fight through the clinging, fractal ice spider webs that splinter now against my cheeks and snap against the outthrust palms of my hands. We didn’t see them.

Zara is quiet as I pull her behind me. Teacake shifts on my shoulder as I turn back, and her breath is coming in great plumes of steam, her eyes wide, lashes coated in fine feathers of ice.

‘You’re sure about this?’ I ask, because Zara is brave, and she’s far more than I ever imagined a friend could be, but she cannot feel the thrum of the acorn on the copper chain beneath my shirt; she does not fight for a family she only barely remembers. For a forest full of magical creatures.

She fights for me, and for Yanny.

She digs the heel of her hand into mine, and she doesn’t speak, but she sets her chin and nods, and we forge onward together, and it gets colder still as we go, and then there’s a row of tall, slender silver birches before us, gathered tight, branches interwoven. We tread around the outside, but there’s no break between them. Their roots are glinting arcs of ice, with limbs tightly laced, and their shadows already alive, boiling across the frozen ground. Tiny creatures nestle up high in the glittering canopy, looking down with large, unblinking eyes. Bats, and squirrels, and stoats – all dark-eyed and white-furred.

His creatures.

He will know we’re coming.

The shadows are waiting.

‘So much for stealth,’ I whisper.

Zara shrugs. ‘Stealth is overrated. What we need to do is burst through roaring.’

‘Really?’ I shiver at the thought, but Teacake yowls on my shoulder with a furry, feline sort of a nod.

Zara shrugs. ‘What’ve we got to lose?’

I stare at her. ‘Ourselves!’

‘We’re already lost.’ She grins. ‘You’ve been lost for a lifetime, Stella. You’re famous for it, remember!’

I stare up at the twisted branches of the trees, willing for a parting, for the slightest gap. We don’t have time to linger, while Yanny fights alone. One step down into the packed snow, four inches deep and creaking like old wood. Teacake drops from my shoulder and prowls ahead, and the trees stand like white-bearded silver sentries, shoulder to shoulder.