Children of all ages were arriving in Winterton, in groups of increasing size, and each child came with an animal companion. Opposite the fairground, on a flat white tundra, two teams were enthusiastically crafting snowballs and stacking them in piles.

‘You just wait,’ one excited girl in polka-dot pyjamas shouted. ‘You’re going to be obliterated.’

‘Oh yeah? We’re going to take you down,’ came a reply.

‘Prepare for utter annihilation!’ someone squealed.

‘You’ll be eating snow for breakfast, lunch and dinner!’ a boy howled in delight.

A snowy owl lifted one of the snowballs, flew across the battlefield and dropped it on the head of an opposing team player. Everyone fell about laughing. The boy splattered with snow grabbed a snowball, hurled it, and the fight began. The shrieks and whoops of laughter made Bianca long to join in. But she gripped the tiny red scarf tied around her wrist. She mustn’t be distracted from the reason she’d come to Winterton.

This place makes people forget, she thought, and looked down at the half-eaten punnet of frozen fruit she held in her hand. Had the berries, or the hot chocolate, made her forgetful? She looked for a place to set the punnet down. She couldn’t risk eating or drinking any more of the food here.

As she and Pordis searched Winterton for Finn, Bianca couldn’t help feeling that she was somehow different from the rest of the children. They were living in the moment, unconcerned with anything except enjoying what they were doing. Shrieks of delight and laughter erupted from a group as their giant snowball rolled away from them. They were building a snowman and called out for her to join them. She smiled and shook her head.

‘Pordis, the children in Winterton are not like me.’

‘Is it because they do not have a brother to find?’

‘Perhaps.’ Bianca wondered why she wasn’t wearing nightclothes when everyone else was.

They came to a frozen lake where a small girl with short, dark hair was skating across the ice in a billowing blue nightie, moving in hypnotic loops. She held her arms behind her, arched like the wings of a swan. Her dance partner was a baby polar bear. It looked at her adoringly, skating in circles around her, sliding on its bottom when it needed to slow down.

For some reason Bianca felt relieved to see this girl and she found she knew her name. ‘Gwen!’

Seeing Bianca, the girl pirouetted, then skated over, the baby polar bear by her side.

‘Hello!’ Gwen greeted her, breathless and smiling.

‘It’s good to see you,’ Bianca said, not knowing why this was true.

‘Sorry.’ Gwen looked puzzled. ‘Do I know you?’

‘I’m Bianca.’

‘Hello, Bianca. You can get ice skates over there, from the funny birds.’ Gwen pointed to an igloo beside the lake. It had an open front with a counter. On the counter was a pile of fish, silver herrings. Two puffins with white breasts, black backs and bright orange webbed feet were hopping around it, getting in each other’s way as they ate the fish. Behind them, lined up on shelves, were pairs of white leather skates with silver blades. The larger bird saw that Bianca was looking at them. It opened its beak wide in a smile, dropping its fish, and pointed a wing at the skates, hopping up and down excitedly. ‘Are you going to skate with us?’ Gwen asked.

‘I can’t.’ Bianca turned back to the girl. ‘I’m looking for Finn, my brother. He’s your age. I was wondering if you’d seen him?’

‘No. Grendel and I have been dancing on the ice since we got here. I haven’t seen anyone.’

‘Well, if you do see him, can you say that I’m looking for him?’

‘Do I know him?’ Gwen looked confused.

‘I think so,’ Bianca replied uncertainly.

‘Oh, OK,’ Gwen said, skating backwards, away from her. ‘If I see a Finn, I’ll say you’re looking for him.’

‘Bianca!’ Pordis’s voice rushed into her head.

‘What is it?’ Bianca sensed fear in the reindeer.

‘We must hide!’

‘Hide?’

‘Quick!’

The reindeer cantered to the igloo where the puffins were playing tug of war with a fish. Bianca sprinted after her.

‘Hello,’ she said to the squabbling birds. ‘Mind if we duck behind here for a second?’

Without letting go of their fish, the birds nodded their orange beaks up and down.

Bianca slid over the counter, dropping into a squat as Pordis nimbly bounded over and knelt down beside her. ‘Who are we hiding from?’ Bianca whispered to Pordis as one of the puffins hopped onto a branch of the reindeer’s antlers, which poked up above the worktop.

‘A bear!’

Bianca was about to protest that they needn’t be afraid of bears here when she heard a voice that made her gasp.

‘I didn’t mean to smash the windows,’ came a booming grumble. ‘It was an accident. I got excited.’

Bianca recognized the voice, and knew in the marrow of her bones that she feared the person it belonged to. Risking a peek over the counter, she saw three children: a boy in a bearskin, and twins, a brother and sister, dressed in grey. Ducking back down, she pulled her orange diary from her pocket, flicking to the drawings she’d done of four children. It was them! Three of them, at least: Quilo, Pitter and Patter. Was the drawing a warning?

‘Jack says it attracted attention . . .’ Pitter said.

‘. . . and we don’t have to mention . . .’ Patter added.

‘. . . that a silver book has gone.’ Pitter sounded fearful.

‘He feels that something’s wrong . . .’ Patter whined.

‘. . . in our wondrous Winterton,’ Pitter concluded.

‘Why is it only what Jack feels that matters?’ Quilo protested sulkily.

‘We don’t wish to be unkind . . .’ Patter sounded insincere.

‘. . . but it was you who left the book behind,’ Pitter said accusingly.

‘And Jack precedes her,’ Pitter told Quilo.

‘Jack’s our leader!’ Patter agreed.

Bianca risked another peep over the counter.

‘I drive the queen’s carriage, and I think I’d be a pretty good leader if I was given half a—’ The boy in the bear suit didn’t finish because the twins were laughing at him. He folded his arms across his chest and harrumphed. ‘If it was that Bianca girl who stole our book, we’ll find her. All we have to do is keep looking.’ He pointed to Gwen on the frozen lake. ‘Look, there’s a girl.’

The twins pivoted to see, then sprinted towards the lake. In unison, they leaped unfeasibly high into the air, their grey shoes growing icy blades before they landed on the ice. Skating hard, they built up speed, somersaulting and twirling around Gwen and the baby polar bear.

Bianca watched them stop Gwen and talk to her. She saw Gwen nod and point towards the fairground.

‘Silly girl,’ Bianca whispered. But she hadn’t asked Gwen not to tell anyone that she’d seen her. Bianca hadn’t realized she should be hiding. She was going to have to be more careful from now on.

Pitter and Patter raced back to Quilo, gabbling as they finished each other’s sentences.

‘Bianca Albedo! She was here.’

‘Her winter creature’s a female reindeer.’

‘Gwen says she’s looking for her brother . . .’

‘. . . dressed in day clothes of a purple colour!’

‘Well, good,’ Quilo burped. ‘That will make her easy to spot.’

‘She mustn’t find the boy.’ Pitter sounded worried.

‘He’s the queen’s favourite toy!’ Patter nodded.

Bianca held her breath as she heard this.

‘Then let’s hurry. If she was just here, we’ll catch up with her easily. Then we can throw her in the palace dungeons until the winter solstice is over. That should calm things down. Jack says she could ruin our scheme, but I say that’s piffle. She’s just a girl.’

‘She could,’ Pitter warned.

‘It’s not good.’ Patter shook her head.

‘Is it really that bad? I know Jack says we can’t have siblings here, that the blood bond between them is too strong and will attract memories, but she must have read The Vanishing World. Her heart will have been pierced by the splinter. It will be freezing, like all the others.’ Quilo waved an arm, gesturing to the children playing in the distance. ‘When the winter solstice arrives, all their hearts will be turned to ice, including hers.’ He marched away. ‘You’ll see.’

‘Catch her we must . . .’ muttered Patter.

‘. . . or lose Jack’s trust,’ agreed Pitter, and they hurried after him.

Bianca clutched her right hand to her chest in terror. Her heart had been pierced by a splinter! She felt the reassuring throb of her pulse beneath her skin. How could her heart be freezing if she could feel it beating? Could she trust her body, or was it her mind playing tricks? She realized with a jolt that she hadn’t felt the cold at all since she’d arrived, even though she was surrounded by ice and snow.

‘Bianca,’ Pordis whispered inside her head, nudging her wet nose against Bianca’s neck. ‘Are you all right, my Bianca?’

‘Pordis,’ she whispered softly. ‘Those children – Quilo, Pitter and Patter, and the one they called Jack – they took my brother from me. They’ve done something to me and all the children here. I think we’re dying!’ Fear and anger fought to rule her head. She gritted her teeth, trying to conquer them both with her mind. ‘I made it here, even though they didn’t want me to. And they say I have the power to ruin their plan, whatever that is.’

‘We will find Finn,’ Pordis said.

‘Yes.’ Bianca looked deep into the reindeer’s brown eyes. ‘And we must be getting close, or they wouldn’t be so worried.’