Heart clamouring, Moll turned to Siddy. ‘Well done, Sid! You did it!’

Siddy set his bow down and watched, wide-eyed, as the kraken wrestled its suckered tentacles over the cocoon. ‘It worked,’ he panted as Frank emerged from his pocket and licked his chin. ‘It actually worked.’

Moll nuzzled into Gryff’s fur, then reached out a hand to touch the cocoon. It was cool and hard and, though the kraken wasn’t giving up, Moll knew that the beast didn’t really stand a chance against the old magic now. She smiled at Bruce.

‘Thank you for rescuing Gryff. You’re fast becoming the most impressive selkie I’ve ever met.’

Bruce clapped his flippers together in delight, but then the kraken slid a large, throbbing eye right up to the cocoon, and the seal pup flattened himself to the raft, his fur bristling.

‘We can’t stay like this forever,’ Moll said. ‘We only have one more night until the full moon rises . . . What do we do?’

The sun was sinking now and, although they couldn’t see it through the maze of islands, its light spilled through the gaps, scattering orange on the sea.

‘It’ll be night soon,’ Siddy said quietly. ‘What if the Night Spinner creeps up on us . . .?’

Frank scurried over the raft towards the cocoon, bashed it with her paw and then let out a little growl at the kraken. But, when the beast barged its slimy body against the shell of light, the ferret shot backwards before clattering into Moll, getting her legs and claws tangled up in Moll’s hair.

‘Urgh, Sid, control your ferret! You don’t see Gryff prancing around all over people’s faces.’

Siddy went to grab Frank. ‘She’s got her paws stuck in something . . . What’s that hanging around your neck?’

Moll glanced at her chest as Siddy yanked the ferret free. Hanging from a piece of string was the whistle carved from antler that Aira had given her. Moll ran her thumb up and down it. ‘Sid,’ she said slowly, ‘I may have an idea how to get us out of this.’

He nodded. ‘So long as it doesn’t involve being catapulted off another burning building, I’m in.’

Moll held out the whistle. ‘Aira gave this to me – she said the giants up in the mountains, the ones who were actually there when the old magic first turned, gave it to her ancestors. She said if I was in need I should blow it and the old magic would come to help.’

Siddy threw his hands in the air. ‘And you didn’t think to give it a quick toot when I was turned to stone or when the castle was burning down or – or when the kraken nearly ATE US?’

Moll’s cheeks reddened. ‘I forgot. There’s a lot to remember with golden feathers and piano strings.’

The kraken slid its face down the cocoon and Siddy edged closer to Moll. ‘Blow the whistle. Now.’

Moll raised it to her lips and blew but the sound that came out was reedy and thin and she felt a stab of doubt that something so small could help them now.

Siddy shook his head. ‘Blow the whistle like you mean it, Moll. Like you believe it’ll help – just as I believed when I made the cocoon.’

Moll blew again, mustering up all the belief that she could, and the sound blared within the cocoon, high and shrill and full of hope. And, even after Moll had lowered the whistle from her lips, the sound rang through the Lost Isles.

‘There’s magic coming,’ she whispered. ‘I can feel it.’

Siddy nodded and then Gryff slipped from Moll’s side to the front of the raft. He looked out towards the passage of sea cutting through the islands, as if he could sense something beyond their vision. A cluster of dark shapes appeared in the sky: a dozen large birds swooping low through the islands towards them, their wings a flash of brown and white against the fading sun.

‘Ospreys,’ Moll murmured, then she looked at Aira’s whistle. ‘Do you think we – we called them?’

‘Even if we did,’ Siddy said glumly, ‘birds won’t be much use against a kraken.’

Moll watched as the ospreys soared towards them before circling above the sea monster. She craned her neck to get a better view. ‘What are they doing?’

And then her stomach plunged. The ospreys were diving – bolts of talons, claws and orange eyes plummeting straight towards the cocoon.

‘No,’ Siddy breathed. ‘The Shadowmasks must have called the birds! Not us!’

The kraken drew back, its tentacles raised in glee as the birds descended, but instead of hammering their talons against the cocoon the birds stretched out their wings at the very last moment, suddenly breaking their dives. Moll held in a scream as the raft wobbled and the endless battering of waves stopped.

‘What’s happening?’ Siddy wailed.

Moll glanced up to see the ospreys clutching the cocoon, which was now soft like cloth and gathered inside their talons like scrunched-up silk.

She raised a hand to her mouth. ‘I think we’re . . . flying!’

The two children rushed to the edge of the raft and when they looked out they saw the kraken far below them, thrashing at the sea with its tentacles. They climbed higher and higher into the twilight, up above the jagged peaks and into a sky strewn with amber clouds. The raft rocked back and forth to the beat of ospreys’ wings and, safe inside the silver-white tent, Moll picked up the whistle and smiled.

‘The old magic came to help us,’ she said.

The birds carried them silently through the clouds, past waterfalls crashing off jutting crags, on up the coast above a copper sea, until eventually the Lost Isles shrank to a few scattered mounds, dark shapes against the dying light. Moll glanced at Bruce who was watching through the cocoon, unblinking, but he made no signal to imply they were going the wrong way. It seemed he wasn’t the only one who knew where the place Willow had called one hundred years deep lay.

There was nothing to be done now but to trust that the birds knew where they were going. So Siddy and Molly sat together, talking long into the night – of what might be waiting for them ahead and of what the last amulet might be – but also of their tree fort and their wagons deep in Tanglefern Forest and of everything they planned to do together once all this was over. And as the ospreys flew on into the night, below a large pale moon, they spoke of Alfie and hoped that wherever he was, he was safe.