Eska could have stayed inside her hideaway for the rest of the day quite happily. But it turned out Balapan was bossy as well as protective and the eagle had yapped outside her door until Eska snatched up her spear and made her way out into the valley again.

Ears pricked for the sound of a sleigh, Eska trudged up the tallest of the hills after the eagle. She paused halfway up, her face shining with sweat, and watched as the eagle soared above her. Balapan’s eyes didn’t roam the hillside aimlessly as Eska’s did. They darted about, from one part of the valley to the next, and as Eska looked harder – deeper – she saw the landscape as the eagle did: the herd of caribou denting the horizon on the other side of the valley; the ghost-like shape of a snow hare darting up a hill; and the footprints of wolves, lemmings and marmots scoring the snow around them.

Eska carried on walking, and watching, and in the hour that followed she found a discarded caribou antler that she realised could serve as a bow to accompany the quiverful of arrows she’d spotted in the hideaway. And she flushed a snow hare from its burrow, which Balapan pounced upon, and Eska decided she would use the animal to make mittens that fitted – the fur for gloves and the sinew for thread.

The wild was still vast and unknowable, but Eska was learning how to carve out her own small place in it. And, though this small place thronged with animals instead of people, Eska discovered, quite unexpectedly, that she was starting to feel a part of it, that she was less alone than she had thought.

She sat on a large rock and thanked the North Star and the snow hare’s spirit for a successful hunt, then she turned to face Balapan, who was perched beside her.

‘We make a good team, you and me.’

The eagle looked at Eska, long and hard, and in those bright yellow eyes Eska saw something precious, something she had almost given up on. The Ice Queen despised her, the Fur Tribe had driven her out, but this eagle was telling her she mattered.

Eska listened to the rush of river water echoing through the valley. ‘I don’t belong to a tribe – I don’t really know where I fit in exactly – but if my tribe ends up just being you and me, Balapan, that would be enough.’

The eagle shuffled nearer until she was so close Eska could see the vane of each golden feather. Then she watched, hardly daring to breathe, as Balapan leant against her. The eagle felt warm and strong and at its touch a deep-buried chord inside Eska’s heart thrummed because to know the closeness of another in a wilderness was to belong, even at the very edge of things.

But, when Balapan flinched, Eska knew something wasn’t right.

Scooping the hare into the game bag she had found in the hideaway, Eska crept after the eagle as it flapped to the uppermost ridge of the hill. The eagle crouched below the skyline, with just her head poking over, and Eska did the same.

At first Eska saw only the towering peaks of the ice-capped Never Cliffs in the distance, but when she brought her gaze closer, down into the neighbouring valley, her stomach lurched. A sleigh, much bigger and much, much faster than the one she had seen before in Deeproots, was speeding between the hills.

They were too far away to hear anything, but Eska watched, rooted to the spot in fear, as six more musk oxen pulled the Ice Queen, flanked by a dozen Tusk guards in glistening armour, closer and closer towards the north of the valley. Eska’s mind whirled. Was there a path from the neighbouring valley to hers? Could a sleigh pass through the ravine above the frozen waterfall?

She tore down the hillside, wincing as she stumbled on a loose stone and her ankle gave way beneath her. She forced herself up and, limping through the pain, carried on down the hill before weaving between the rowan trees by the river and clambering over the rocks leading down to the waterfall. Balapan slipped into her nest – a lookout should anything happen – and, with her ankle throbbing and her heart hammering, Eska squeezed through the opening in the ice and closed the hideaway door behind her.

Trying to ignore the burn in her leg, she waited, crouched in the tunnel before the window, her eyes wide with fear. She had drawn the sack curtains across the pane that morning, but through the narrowest of cracks Eska looked out now.

There was nothing for a long time and, as the light began to fade, Eska wondered whether perhaps the Ice Queen had failed to find a way through the valley and had given up and gone back to Winterfang. But then, out of nowhere: the sound of a sleigh from the north.

The Ice Queen was coming.

Eska drew back from the window, pinning herself against the tunnel wall. She listened as the sleigh pulled to a halt somewhere nearby and the grunts of the cursed musk oxen rumbled into the twilight. Eska’s heart thumped at the clink of the Tusk ice armour, but she kept absolutely still. Then the Ice Queen’s voice came, loud and sharp and so close Eska could almost feel the words slipping down her spine.

‘I summon you foothills under my hold.

Take the girl and the boy into your fold.’

Eska’s breath caught in her throat. The girl and the boy . . . Did the Ice Queen mean Flint? Had her candles whispered of his presence in Winterfang? And had Eska put him in danger even without the Fur Tribe taking her in?

The Ice Queen’s voice dropped as she addressed her guards. ‘The hills will only remain under my command until the midnight sun rises – in eleven days’ time. I must achieve immortality before then so I can extend my power over every living thing in Erkenwald for ever: hills, rivers, forests, lakes.’ She paused. ‘And, once I’ve swallowed the voices of the Fur and Feather Tribes, I will kill every single one of them so that you, my Tusks, can share in the glory of an Erkenwald ruled by dark magic.’

There were murmurs of excitement from the guards, then the Ice Queen added, ‘But if I fail to steal these voices in time I will vanish with the midnight sun and all those touched by my magic – my prisoners, Eska’s memories and my Tusk Tribe – will perish alongside me.’

The guards were suddenly quiet and the Ice Queen went on. ‘I must ride back to Winterfang; Slither’s contraption is complete and I want to see if it does what he says it is capable of – but you will stay and search Deeproots. I want that forest patrolled. A boy from the Fur Tribe helped Eska escape and he must be taught a lesson. The girl needs to be isolated and helpless if I am to take her voice before she learns about the power of the Sky Song.’

At the mention of the Sky Song, Eska risked a glance through the window. The Ice Queen was standing on a rock overhanging the river, her fingers wrapped round a staff of glistening black crystal. It was taller and thicker than her previous sceptre and at the sight of it Eska withdrew. The Ice Queen thumped her staff against the rock and the musk oxen lashed their horns against the nearby branches. Moments later, Eska heard the lurch of a sleigh and then, finally, there was silence once again.

She peered out of the window to see the silhouette of the eagle standing up in the nest on the ledge. Eska breathed a sigh of relief, but as she thought of the hills boxing in the valley, dark and tall and bidden to the Ice Queen’s commands, she shivered. And what was this mysterious Sky Song the queen spoke of? Did it have something to do with her voice? She reached a hand up to her throat, suddenly frightened by what might lie inside it, then she shook herself and lit a lamp.

Eleven days. . . that’s what the Ice Queen had said. Just eleven days until the midnight sun and the queen took power over the whole kingdom. Eska gulped. Even if the Ice Queen failed to achieve immortality in that time the consequences would be disastrous: the prisoners at Winterfang would die and her memories – every single recollection of her past – would be lost for ever. Eska’s heart was racing now. There was no more time to prepare; she needed to press on into the Never Cliffs as soon as possible to find the Feather Tribe in the hope that they could help her. But her ankle was pounding and, as she eased off her boot, Eska saw that it was purple and swollen. She cursed under her breath. It would be a few days before the sprain healed enough for the journey onward.

Eska looked at her reflection in the metal of a dagger she had found in the hideaway. A girl stared back at her, but despite the sunken cheeks and straggled hair, this girl’s eyes were hard. The Ice Queen said she wanted Eska isolated and helpless, but that wasn’t going to happen.

Because she wasn’t the timid little prisoner she had been, locked inside the music box at Winterfang. She was out in the wild now – with a golden eagle by her side – and for the first time since leaving the palace, Eska dared to hope that the sum of all that might be enough against an Ice Queen with the power to conjure whole valleys to do her bidding.