An eerie silence followed and for a while all Flint, Eska and Blu could do was stare at the river below them. Then the Diamond Dust slipped away through the trees and Flint put an arm round Blu’s shoulders.

‘That was close,’ he panted.

‘I think mentioning Needlespin before we set off from the Giant’s Beard would have been helpful,’ Eska replied.

Flint glanced at Blu. ‘I didn’t want to scare her.’

Blu looked down through the branches and wailed.

Eska rolled her eyes. ‘Because finding out this way was so much better . . .’

Flint turned to Blu and hauled her on to a sturdier branch. Then he looked at Eska. ‘You and Balapan saved us back there. We’d never have survived all that without you.’

Eska grinned then she looked around. ‘Maybe don’t tell Tomkin we got Blu jammed into the top of a very high tree.’

Blu pulled at a branch. ‘We tell Ma.’

Flint laughed. ‘Let’s kick these skis off and climb down.’

Balapan was waiting on a rock at the foot of the trees and as they clambered through the lower branches Flint watched as she swooped to Eska’s shoulder and leant against the girl’s cheek. Eska stretched up a hand and ran it over the eagle’s wing and Blu shuffled through the snow towards the eagle.

‘Want to hug Bala.’

It was the name Blu had started using for the eagle and neither Eska nor Flint had corrected her.

‘I’m not sure eagles are very good at hugging,’ Eska said softly. ‘Animals are a bit different from humans.’

Blu tilted her head. ‘Animals hug. Just not with arms.’

And, as she raised her little hand towards Balapan, the eagle loosened her wing and brushed it against Blu’s palm.

‘There. Hug. See?’

Flint ruffled her hair. ‘I’m proud of you, Blu. You were brave just now. Really brave.’

They shared out some mountain cranberries and water, then they strapped on their skis and looked down at the river winding on through the Never Cliffs. A cluster of tundra swans were feeding on algae where the afternoon sun had thawed the ice, but other than that the landscape was absolutely still and, just as Flint was about to suggest they get going, Eska gasped.

‘The river,’ she said quietly. ‘Before the mountains close it in, there are lots of little tributaries branching off from it. And, well, if you squint hard enough, the river almost looks like a giant feather . . .’

Flint peered at the scene below and his eyes widened. ‘You’re right.’

‘Feather Tribe close,’ Blu said.

Flint thought about it. ‘I once heard that the Tusk Tribe used to stand on the cliff tops to the north of the kingdom, then look down at the icebergs and read messages in their shapes.’ He paused. ‘Maybe the Feather Tribe use landmarks as signs, too. Blu’s right; I think they are close . . .’

The three of them skied quickly down the mountain and rather than crossing the frozen river – the episode with the thunderghosts was still fresh in everyone’s minds and Needlespin’s remains lay scattered across it – they hastened along beside it, following its curve and jumping over the tributaries which snaked out into the mountains. They glanced around, eagerly searching for any signs of civilisation, while Balapan flew overhead. And, when Pebble realised that Needlespin was no longer a threat, he leapt down from Flint’s hood and joined in the hunt.

The fox pup bounded ahead, sniffing at the snow and padding carefully across the tributaries, but, when the mountains closed in again and just the main river ran on through a narrow gully, Pebble started barking.

‘Shhhh, Pebble,’ Flint hissed. ‘We can’t afford to draw attention to ourselves.’

But still the fox pup barked and Flint noticed then that he was pawing at the snow on the mountainside to their right.

Eska frowned. ‘What is it?’ she whispered. ‘What has he found?’

‘I think he’s caught a scent and wants us to follow it.’

Flint hurried closer to Pebble and noticed a shelf of rock hanging out above the path, a few metres above the fox pup. In a swish of feathers, Balapan landed on it, then she stayed very still.

‘Something about this mountain is important,’ Eska said slowly. ‘Both Pebble and Balapan know it.’ She took a step beneath the ledge and her eyes widened. ‘Look at this!’

Strung from the tip of the ledge right down to the base of the mountain was a giant spiderweb laced in ice. It hung in delicate spirals, each loop coated in dashes of frost as thin as silver eyelashes, and Flint knew, as he gazed upon it, that magic was involved. Then he saw how: the centre of the web was a cluster of ice and on it sat a spider. It was the size of a fist and as clear as glass.

‘An ice spider,’ Flint murmured. ‘They usually spin ice unless it’s a clear night, then they spin moonlight.’ He paused. ‘It’s beautiful, but how is it going to help us?’

They watched quietly as the spider left the middle of its web. Then Flint understood – the web was not complete – the spider was spinning still and the gossamer it spun did not fill the spaces left with ordinary loops. Words were appearing, silver words that shone in the twilight.

‘It – it’s trying to tell us something,’ Eska breathed.

No one dared speak until the spider had stopped and two words glistened in the web.

CHIN DOWN

Flint turned to Eska. ‘Chin down? I don’t understand.’ He threw his hands up. ‘We’ve only got three days to stop the Ice Queen and we’re faced with an ice spider spinning nonsense! We need to find the Feather Tribe!’

‘Chin up,’ Eska said. ‘I heard you say that to Blu when you were trying to encourage her to keep going through the Never Cliffs this morning.’

Flint turned away from the web and looked on down the path through the mountains. ‘Yeah, well, this spider got it wrong then because it’s saying Chin Down which makes no sense at all.’

He grabbed Blu by the hand, but to his surprise he found her reluctant to move on.

‘Come on, Blu. We’ve no time for this!’

But his sister didn’t move. She kept her head down and her eyes fixed on the base of the mountain. ‘Chin down,’ she said. ‘Put chin down, Flint. Look.’

Flint tucked his chin into his chest and followed Blu’s gaze then he saw what she was looking at – something they would have missed completely had Blu not listened to the spider’s instructions. There, nestled into the base of the mountain, was a very faint, dome-shaped crack in the snow as if, perhaps, someone had opened a way into the rock not so long ago.

Flint and Eska brushed the snow away until they found what they had been looking for: a door carved into the cliff face with a small skull acting as a handle.

‘A bird skull,’ Flint breathed. ‘Snowy owl, it looks like.’ And then his face broke into a grin. ‘The snowy owl is the symbol of the Feather Tribe. I think we’ve found the way into the Lost Chambers!’

They turned to see the spider drop to the ground then it scuttled down the path, on into the mountains. But as it went they noticed it didn’t leave a trail of thread or tiny pricks where its feet marked the snow. It left footprints. Human footprints. And as Flint looked at them he remembered Whitefur’s words: Good luck in your search for the Lost Chambers. And remember, you have the wild on your side and the wild doesn’t play by ordinary rules.

‘That was a Wanderer, wasn’t it?’ he whispered to Eska. ‘Like how Whitefur was an Erkenbear but also a man. That spider – it was . . . I don’t know what it was! But it was one of your kind, I’m sure of it.’

Eska’s eyes were wide. ‘Do you think one day I’ll learn how to shape-shift into wild creatures?’

Flint smiled. ‘Wouldn’t put it past you.’ He looked at his little sister. ‘You were right to trust that spider, Blu; to wait until you understood what it was saying.’

Blu nodded. ‘I clever.’

And though Flint was used to waiting for Blu, used to her dawdling behind and not understanding, this time she took his hand and, shivering, led him into the mountain.

Eska followed with Balapan on her shoulder. They were in a passageway large enough to stand in and balanced on the rocky ledges either side of them were halved eggshells of every colour imaginable – speckled green, turquoise, mottled purple, gold – and inside each one a candle flickered.

Flint pulled the door shut behind them, then his eyes travelled over the eggshells as they walked on. ‘Peregrine, pintail, lesser snow goose, red-winged sparrow, mountain bluebird. This is the Feather Tribe all right! Only they would know where to find the eggs of birds like these.’ And then he gulped as he remembered the reception his tribe had given Eska. He slid a glance at his friend who was looking equally nervous. ‘Just leave the conversations to me,’ he said.

Eska nodded, then she laid her hand on Balapan’s talons and Flint thought it looked a little like the bird and the girl were walking hand in hand.

Pebble hurried ahead, but, after a few minutes, he stopped and cocked his head to one side. Because blocking the way ahead was a large bird with a long, scooped neck and a fan of white feathers that filled the entire tunnel. It looked like a peacock and yet its colouring was different; this bird was as white as freshly fallen snow.

Flint blinked in disbelief. ‘That’s a moonflit!’

Eska gulped. ‘Is that good or bad? I didn’t come across them in my training with Balapan.’

Flint rubbed his eyes. ‘Neither. It’s just – unlikely. Impossible even . . . These birds have been extinct for centuries!’

Eska peered closer. ‘Look at its feathers. Each one has a circular pattern on it.’

Flint nodded. ‘Eyes, our ancestors used to say, because moonflits can see beyond ordinary things – into hearts and minds and—’

Blu squealed as the white markings flicked a fraction to reveal hundreds of grey, staring eyes.

‘I don’t know how the Feather Tribe got hold of this creature but I think it’s acting as a guard,’ Flint whispered. ‘I think if the moonflit lets us past it means it trusts us.’

Very slowly, the feathered eyes opened and closed and then the bird lowered its tail feathers into a sweep of white and backed into the shadows so that the group could see what lay beyond. Darkness. A space so black there was no difference between blinking and keeping your eyes wide open. Flint lifted Pebble into his hood, then, holding Blu’s hand still, he shuffled forward.

Eska tiptoed after them. ‘Is it a dead end?’

Blu moaned. ‘I want home, Flint. Tired. Cold.’

Flint squinted into the black, but, just as he was about to speak, there was a creak and then a click behind them. And he knew immediately what had just happened. A door in the dark had been closed.

They had walked straight into a trap.