Flint knelt by his sister and wrapped his arms around her.

‘It’s okay, Blu. It’s okay.’ Pebble crawled out of his hood and licked Blu’s cheek. ‘I’ve got you now.’

Blu’s bottom lip was trembling. ‘Snow alive, Flint. It angry. Why the snow angry?’

Flint brushed the ice crystals from her furs. ‘It’s gone now, Blu. We’re safe. It’s all right.’

And then he turned to face Eska. She was there on the hillside still, just a few metres above them, but this was not the feeble girl he had helped escape Winterfang. This girl was different. Her stance was tough, her red hair was braided with feathers and plaits, and on her shoulder there perched a golden eagle. It was the same one Flint had seen trapped in the snare before Deeproots – he could see the scar on its left talon – but what on earth was it doing with Eska? And how had she survived in the wild for so long? He scooped up Pebble and stumbled to his feet, but, on seeing Eska, Blu pushed past him.

‘Eska!’ she cried, clapping her hands. ‘My friend! I miss you!’

Balapan launched herself into the sky, unsure what to make of the bundle of fur charging towards her, but Blu wasn’t fazed. She flung her arms round Eska and squeezed her tight.

Eska blushed. ‘Hello, Blu.’

The little girl drew back. ‘Flint looking for you in forest!’

Flint plucked a clump of ice from Pebble’s fur. ‘Quiet, Blu.’

She scrunched up her nose. ‘Flint looking for you, Eska! At night when Tomkin sleeping. And today on hunt. Always looking with his magic glass!’

Flint was suddenly glad that his magnifying glass was tucked away in his rucksack and not out in his palm, searching for Eska’s tracks, as it had been only a few hours before.

‘We came out to the foothills to hunt ptarmigan, actually. The Tusk guards are patrolling the forest now and we can’t access our usual hunting spots.’

Blu smiled. ‘We came to find you, Eska. Flint forget.’

Flint scowled at his sister. ‘We strayed a little further than previous hunts this morning to, um, find the best ptarmigan . . . but we didn’t expect to stumble into the Ice Queen’s enchantments.’ He looked around the valley. ‘So, you found another tribe to take you in then?’

Eska glanced at Balapan wheeling above them. The bird was wary of the visitors, but she could tell that these ones meant no harm. ‘Yes.’

Flint frowned. ‘The Feather Tribe? In the Never Cliffs?’

‘No.’ Eska picked up her quiver and slung it over her shoulder. ‘It’s just me and Balapan.’

The eagle cried above them, carving its circles in the bright blue sky.

Flint shook his head. ‘You survived out here, in the wild, without a tribe?’

‘I’ve got a tribe,’ Eska replied. ‘It’s just not very big yet.’

‘But – who taught you to hunt? How did you find shelter?’

Eska shrugged. ‘Balapan.’ Then she added, ‘The golden eagle.’

‘But . . .’ Flint’s words trailed away.

‘She showed me the hideaway, then she taught me to hunt,’ Eska explained. ‘Fish first, down by the river, then hares up in the burrows on the ridges. Ptarmigan, too, once I’d bent the caribou antler into a bow, strung it with sinew and fletched my arrows.’ The words spilled out, toppling over each other in their strangely magnetic way, as Eska negotiated her first proper conversation since leaving Deeproots. And all the while Flint listened, his jaw open. ‘We get along pretty well, Balapan and me, so long as I remember to wash up my dishes after hunts. But I suppose washing-up is to be expected in tribes. It’s not exactly fun though, is it?’ She paused. ‘Sorry, I forgot you don’t much like talking.’

Flint was too shocked to speak, but Blu simply rolled her eyes. ‘Keep up, Flint. Eska good hunter.’ She grinned. ‘Let’s eat Eska food.’ There was a growl of approval from Flint’s arms. ‘Pebble hungry, too.’

And Flint was surprised to see that Eska didn’t flinch at Blu’s demands or even seem to hold a grudge about what the Fur Tribe had done to her when she’d asked to be welcomed in. She simply handed Blu the necklace she’d found in the snow and nodded towards the river.

‘This way to the hideaway,’ she said.

Flint was quiet as they walked and while Blu chattered away to Eska he glanced up at the eagle soaring over the valley. It didn’t seem to be following them exactly, but he could tell that it was watching their every move. Flint knew about the bonds between animals and tribes during hunts – he’d learnt all about that from his pa – but no one had ever spoken of an animal teaching a person the ways of the wild. And yet somehow Balapan had helped keep the girl alive, against all the odds.

He walked on in silence, but, when Eska led them behind the waterfall to the wooden door built into the rock, Flint couldn’t hide his astonishment.

‘You – you found the Giant’s Beard!’ he stammered. ‘The waterfall that freezes all through winter and hides Erkenwald’s most secret food store . . .’

Eska pulled the door open. ‘Well, technically, Balapan found it.’

The eagle settled into its nest on the ledge outside and Blu patted Eska’s back. ‘This amazing, Eska!’

Flint stepped inside and his eyes travelled over the beds, table and chairs and the little pieces of the wild Eska had collected: red quartz from the riverbed on the windowsill; pine needles scattered over the floor; and snowy-owl feathers twisted round the base of a lamp.

‘It really is . . .’ Flint murmured as he closed the door. And then he realised what he’d said and reached for some new words. ‘Snargoyles – that’s what we ran into back on the hill.’

Eska lit the stove while the others took a seat. ‘Snargoyles? So that’s what happens when the Ice Queen calls the hills to obey her . . .’

Flint nodded. ‘Snow hexed by dark magic does strange things. Lofty said he saw snargoyles in this valley shortly after the battle last year and none of us came back after that.’ He paused. ‘Until we decided to hunt here today, of course.’

‘Without bows or arrows,’ Eska said, avoiding his eyes.

Flint shifted in his seat. He couldn’t help feeling he was losing control of the conversation, something that often seemed to happen with Eska. He sank into silence as Eska reached for the plucked ptarmigan. She threw one, still raw, to Pebble who squealed with delight and then she knelt by the fire as the meat cooked.

The silence dragged on and Flint’s eyes widened as Eska plated up the meat and handed the food around.

‘Thank you,’ he said, after a while. ‘For the ptarmigan and for helping us out with the snargoyles. I don’t know what would have happened if you and Balapan hadn’t shown up.’

‘Just keeping a promise,’ Eska said quietly.

Flint thought back to her words on his sled: One day I’ll repay you for rescuing me. They were words that he had scoffed at and yet Eska had kept to them. Because of her courage and loyalty he and his sister were still alive – and, on realising that, something inside Flint thawed. This was a girl he and his tribe had vastly misjudged.

He took a deep breath. ‘I think, maybe, I was wrong about you, Eska.’

Eska smiled then, a wide smile that reached her ears, and Flint found himself wondering whether birthplace, parentage and appearance were really the things that you should list people under. Somehow courage and loyalty seemed like better markers.

Eska launched into all that had happened since leaving the Labyrinth: being chased on to the foothills by the Ice Queen’s sleigh, Balapan saving her, the queen’s plans to curse Erkenwald and wipe out the Fur and Feather Tribes, and the mysterious mention of the Sky Song.

Flint tried to imagine his beloved forest cursed by the Ice Queen’s power: trees rotted through, lynx hexed to obey her, the Labyrinth destroyed and his whole tribe gone. His heart trembled at the thought.

After a while, Blu got up to play with Pebble, but Flint and Eska kept talking through the day and, though he said nothing, Flint couldn’t help noticing the change in Eska’s voice. Her body was sturdier, even the way she moved was more decisive, but her voice – although still strangely captivating – was undoubtedly weaker. Once or twice, she tried to clear her throat, as if she could tell there was something wrong and was embarrassed by that fact, but it didn’t sound like a tickle or a cough to Flint.

Eska leant back in her chair and sighed. ‘I still don’t know who I am. Or why my voice is important. Or what this Sky Song is. Or even how I’m going to stay hidden from the Ice Queen.’

‘I don’t think people stop evil by staying hidden.’ Flint looked through the window at the afternoon shadows cast by the rowan trees. ‘I think they stop it by standing out.’

Eska pulled her hair back from her face and wound it into a plait. ‘But the midnight sun rises in five days! How—’ Flint gasped and Eska spun round. ‘What? Am I doing the conversation wrong again?’

‘Look back at the window for a second,’ Flint murmured, then he leant forward and peered at her neck. ‘You have a birthmark just below your hairline.’

‘Oh,’ Eska replied. ‘Is that good or bad?’

Flint grinned. ‘It’s big – the size of my fist – and the pattern is so clear I could have drawn it on! It’s the Little Bear, the constellation of the Sky Gods!’

Eska’s face paled. ‘The Ice Queen told me that I bore the mark of the Gods – that it was the proof that I was cursed. I didn’t know what she meant, until now.’

Flint shook his head. ‘You’re not cursed, Eska.’

‘How do you know? I’ve got the mark to prove it!’

Flint shook his head. ‘Because since we met you’ve got me thinking. Two whole armies of warriors weren’t enough to defeat the Ice Queen last summer and Tomkin’s rebellion will be no different, no matter how many extra training sessions he organises.’ He paused. ‘I know that Erkenwald’s magic can be used for good.’ His face reddened at the words kept secret for so long. ‘And I think your birthmark is a sign that your voice is the key to defeating the Ice Queen.’

At the mention of her voice, Eska winced, and Flint couldn’t help feeling that she was holding a secret back. She grabbed her spear. ‘Raise your knife, too, so that I’ve got a mirror behind me. I want to see the birthmark.’

Flint did as she asked and as Eska looked at the constellation stamped on her skin she swallowed. ‘I was planning to leave for the Never Cliffs today to seek out the Feather Tribe, but then the snargoyles attacked.’ She gripped her spear. ‘It’s too late to go on now but I need to set off at first light tomorrow because time is running out. The Feather Tribe might know something about my past or the Sky Song, and to defeat the Ice Queen I’m going to need to know more than I do now.’

Flint nodded, then he was silent for a few minutes. He knew he should be getting back to Tomkin – this was exactly the sort of ‘detour’ his brother was always warning him about – but Flint’s gut was telling him to go on with Eska. He thought of his ma trapped in Winterfang, and Erkenwald emptied of the Fur and Feather Tribes, and its rivers, mountains and oceans cursed by the Ice Queen. What if, by journeying to the Never Cliffs with Eska, he could prevent all that? What if he could stage a rescue mission that worked not only for his ma, but for all the others prisoners, too, a mission that would make Tomkin proud of him for once?

But there was Blu, currently dangling titbits of food before Pebble who jumped up and gobbled them down. He couldn’t leave her here. She didn’t have the co-ordination to hunt on her own or the strength to spend nights in the wilderness with no one by her side. But he couldn’t tell her to go back to Deeproots – she wouldn’t find her way without his help – and going back to the Labyrinth with her would mean risking the Tusk guards and Tomkin’s rules. But to come with him, if he went on with Eska? She wouldn’t keep up in the Never Cliffs: she wouldn’t be able to cope with the dangers around them.

‘I want to come with you, Eska,’ Flint said quietly.

And Eska nodded as if, perhaps, she could read him a little better than he thought.

‘But Blu,’ Flint whispered. ‘She’d be slower than us. And she wouldn’t understand things.’

Eska watched Blu rolling on the bed with Pebble. ‘We’ll look after her,’ she said. ‘You, me and Balapan.’

Flint bit his lip. ‘It’s a big thing looking after her. Bigger than you think.’

Eska nodded. ‘I know. But that’s what tribes do.’

Flint was taken aback by her words. Not many people had the patience for Blu – and fewer still the understanding – but somehow Eska, an outsider he knew next to nothing about, seemed to have both. And her acceptance stirred something deep inside Flint’s heart.

Eska looked around the hideaway. ‘We’ll leave at first light, after—’

Blu hurried to the window. ‘Something there,’ she said, frowning. ‘Something in the trees.’

Eska looked over Blu’s shoulder. ‘Balapan’s still in her nest, Blu. It’s okay. She’d let us know if there was anything to worry about.’

Blu shook her head. ‘Something there. I saw it. Big shape.’

Flint drew Blu back to the table. ‘Come on, Blu. It was probably just—’

A shiver rippled through Flint because there were footsteps crunching through the snow outside, accompanied by a low, husky breathing. Someone or something was approaching the Giant’s Beard.

Eska grabbed her spear with one hand and Blu with the other, then Flint edged forward on silent feet before lowering an eye to a small crack in the door. His stomach tilted.

White fur. An eye as black as coal.

‘Erkenbear,’ he whispered, his voice laced with dread.