Once upon a warm winter, in the dawning darkness of December, a boy was found in the city rose garden. He was dressed in navy starred pyjamas. The pale skin of his face was duck-egg blue and sparkled with snow crystals. Every strand of his fine blond hair was an ashen icicle. His eyes were closed, his expression serene. His feet were submerged in a pedestal of ice.

The boy looked like a statue. He was frozen solid.

‘How is this possible?’ said the police officer, gazing with horror at the lifeless figure and thinking of her own children, tucked up in their beds. ‘Sarge says a five-year-old boy matching his description was reported missing half an hour ago. His name is Finn Albedo.’

Without taking her eyes off the child’s face, she removed her hat and nervously ran her fingers through her hair. ‘Doctor, his parents are on their way here, now. What am I going to tell them?’

‘The truth.’ The doctor was wrapped in the thick woollen coat that accompanied him on late-night calls. He stepped back from the frozen

boy. ‘You can tell them that he is alive. I can hear his heartbeat through my stethoscope. It’s very slow, but he is alive.’ He shook his head, and his melancholy voice took on a note of wonder. ‘Never in all my years have I seen anything like this.’

The sound of footsteps made them both turn.

Mr and Mrs Albedo ran into the rose garden, clutching the hand of a solemn-faced eleven-year-old girl with fierce hazel eyes and bobbed brown hair. She was wearing a winter coat over her nightie and wellington boots with no socks.

The sight of her brother hit Bianca hard, snatching the breath from her body. He was so still, so blue. Framed by twinkling stars and spotlit by the full moon’s beam, he looked unsettlingly beautiful. She dropped her mother’s hand.

‘Is he dead?’ Bianca whispered, terror rising inside her.

‘Now, you mustn’t panic,’ said the doctor.

But Bianca was remembering the fight she’d had with Finn at bedtime. He wouldn’t let her see the book he’d borrowed from the library and she’d got cross, calling him the most annoying little brother in the whole world. Finn had cried and she’d lost her temper, saying he was behaving like a baby and that she wished she had a little sister instead. Now, her cruel words and his tears echoed in her head. Had he run away because of her?

‘Who did this?’ Bianca’s dad asked angrily. ‘Tell me who did this to my son, right now!’

‘We don’t know, sir.’ The officer took out her notepad. ‘All we know is that a person named Jack Dewynter was taking a night-time stroll through the park and found your son . . . like this.’ She gestured. ‘He reported it to one of the constables on night duty.’

‘We put him to bed, like normal, with a book . . .’ Bianca’s mum’s voice was high and wavering as she reached out and touched Finn’s icy arm. ‘But I found his bedroom door open. His bed empty!’ She pressed her lips together, trying not to cry, and tucked a wisp of her auburn hair behind her ear. ‘He’s only five.’

‘How did Finn get here? Like this . . . here, in the park?’ her dad asked the police officer, struggling to make sense of what had happened. He was a practical man, a problem solver, but you couldn’t solve a problem if you didn’t know what it was. And for the first time Bianca saw that he had wrinkles across his forehead and looked old.

‘We don’t know, sir. Nothing like this has ever happened before. It’s very . . . strange.’ The officer shrugged apologetically. ‘The doctor says his heart is still beating.’

‘He’s alive?’ Bianca’s dad’s voice rang with a tremulous note of hope, and they all turned to the doctor.

‘Hem . . . well, yes,’ the doctor said, sounding cautious. ‘He has a heartbeat.’

‘Then we must free him!’ Bianca’s dad slid off his coat, passing it to her mum, signalling that she should put it on Finn. ‘Should we warm him up?’

‘Ah . . . er . . . well, in severe cases of frostbite one must be on the lookout for muscle and bone damage. Although this doesn’t look like frostbite to me. Er . . .’ The doctor stroked his chin. ‘It is a most unusual case. Until we know what has actually caused this, I really don’t think it’s a good idea to try and move your son. We don’t want to . . . accidentally hurt him.’

‘Frozen things can shatter,’ the police officer said, and Bianca’s mum gasped with horror.

‘What’s wrong with you?’ her dad snapped at the police officer, putting his arm round her mum, whose head had bowed and shoulders slumped.

‘I apologize. That was thoughtless of me. What I meant was—’

‘I know what you meant,’ Bianca’s mother sobbed.

Stepping away from her parents, Bianca reached out, taking her brother’s icy hand. He was as cold as stone. The

pedestal raised him half a metre, so he was taller than her. She looked up at his face, and her thoughts jumped back a week, to when she had chased him up the stairs after his bath, pretending to be a hungry monster trying to eat him. How warm and pink he’d been when they’d tumbled onto his bedroom carpet together, laughing.

‘I don’t really want a sister, Finn,’ she whispered, her heart aching. ‘I was being mean when I said that. I’m sorry. I really am. You’re not a baby. You’re the best brother in the world.’

Silence.

‘What should we do?’ her dad asked, sounding desperate and helpless. ‘Tell us. Please.’

‘This is an unprecedented situation.’ The officer was shaking her head. ‘There was a girl who fell through the ice into the boating lake three years ago, but this . . . this is different.’

‘Somebody did it to him,’ Bianca said, and the adults turned their heads. The police officer blinked, looking surprised, as if she’d forgotten Bianca was there. ‘Finn didn’t freeze himself. Somebody froze him!’ She scanned the rose garden. It looked different at night. Less friendly. ‘Why aren’t you searching for clues?’

Bianca saw several curious bystanders peering at her brother through a gap in the hedgerow. A couple, leaning into each other, looked as if they were on their way home from a night out. Behind them stood a towering man in a long black coat, dark glasses and a top hat. He was watching her. She scowled at him, then turned her angry eyes to the officer. ‘You should be interviewing people, looking for clues and detecting things! What’s happened to Finn is a crime. What did that Mr Dewynter man say? Did you arrest him?’

‘Neither taking a walk nor reporting something is a crime.’ The police officer shook her head.

It dawned on Bianca that Finn being frozen might not be a crime either. Could something be a crime if it had never happened before?

‘Don’t you worry about your little brother.’ The police officer’s mouth curved into a fake smile. Bianca recognized it as one that grown-ups used when they wanted children to stop asking awkward questions. ‘We’re doing everything we can for him.’

Bianca glared at her. If the police weren’t going to investigate properly, then she would do it herself.

Kneeling down, she moved carefully around the pedestal of ice, studying it. It was transparent, and with the help of the full moon, she could see crushed grass through the base.

‘Well, the ice didn’t spring out of the ground and catch you like a Venus flytrap,’ Bianca muttered to Finn. ‘If it had, there’d be no grass underneath it.’

Scattered around the base of the pedestal were large hailstones. Bianca picked one up, rolling it between her thumb and forefinger. For weeks the weather had been wet and warm. There hadn’t even been a frost yet. Where had the hailstones and ice come from?

Ignoring the burning cold, Bianca ran her hands over the pedestal’s surface. The back and the sides were smooth, but the front had indentations. Her fingers explored them. ‘Words!’ she gasped, bringing her nose closer to the ice.

In carved italic capital letters, she read:

DARK DAYS GROW EVER WARMER.

WINTER’S ON THE RUN.

ICE BECOMES A LIQUID,

BENEATH A SEARING SUN.

WHEN THE SEASONS ALTER,

SOMETHING MUST BE DONE.

WITH THE HEARTS OF CHILDREN,

WINTER WILL LIVE ON.

‘Mum! Dad! Look!’ Bianca cried. ‘There’s writing here! What do you think it means?’

Her parents, the officer and the doctor all crowded around to see, reading the words with expressions of disbelief and revulsion.

‘Is this someone’s idea of a sick joke?’ Her dad almost choked as he spoke, he was so angry.

The police officer and doctor shook their heads, not daring to reply.

The poem made no sense to Bianca, but she felt it must be a clue. ‘I’m going to find out who did this to you, Finn,’ she whispered, looking up at her brother. ‘I promise. I will save you.’