Lizzie spoke until morning. Then, as light seeped in under the shutters, her head finally slumped forwards. Felix grew alarmed: she wasn’t … was she? The rise and fall of her chest told him no, she wasn’t dead. She’d simply fallen asleep.

Relieved, he got to his feet, stretching his legs, which had grown stiff from too much sitting in expensive chairs.

‘I must go to bed,’ said Mary, rubbing her eyes. ‘Fetch me when she wakes, will you?’

‘I expect she’ll come to you first,’ Felix replied. ‘She’s very set on getting her sister back.’

Mary frowned. ‘So you believe her? You think the child we brought with us from Eden Court is her sister?’

Looking down at the sleeping girl, Felix knew now who she reminded him of. Her hair was dark blonde, not white. Straight, not curled. Yet she resembled that face he’d seen yesterday at the Shelleys’ window. She must truly love her little sister to come all this way from England, blind and on her own.

‘Lizzie’s ever so brave,’ Felix said.

Mary stood up and smoothed her dress. ‘She tells a good story, I’ll grant her that.’

Felix stared at Mary.

‘She hasn’t come just to tell a story,’ he said. ‘What she’s told us seems to be the truth.’

‘Oh,’ Mary faltered. ‘Oh I see … dear me … So you do believe what she said?’

‘I think so, yes. It’s your friend you should be more concerned about. This Miss Stine isn’t all she seems.’

Mary sank heavily into her chair again. She looked pale and suddenly lost.

‘You’re right,’ she said, head in her hands. ‘Though it pains me to admit it, Lizzie’s account of what happened at Eden Court is a fair one. We were part of something awful that night; we encouraged it.’

When Mary glanced up, her face was full of despair. ‘Oh, Felix. I believe I’ve made the most terrible mistake.’

In less than an hour, Lizzie awoke.

‘My sister! Is she here? Is she safe?’ She tried to get up, only to fall back onto the chaise longue.

‘Hush, you’re still weak,’ Mary said. ‘In a few days, when you’re stronger, we’ll take you to her.’

But Felix didn’t think it should wait. And he was getting rather used to speaking his mind.

‘Mary, your house is but a short walk away,’ he said. ‘It’s best for everyone if we do it today.’

Now it was Mary who looked scared – and terribly tired. He felt it too – that grittiness in his eyes and the throb in his head. In the end, it was agreed they’d have breakfast first.

When they came to leave, they found the front door was bolted.

‘Who is this person following you, Lizzie?’ Felix asked, recalling why he’d locked the door last night.

‘Not following me, exactly. She caught the same boat across the Channel but she probably had a smart cabin whereas I slept in the hold. I didn’t even know she was on board till we docked in France.’

Felix caught Mary’s eye. The look they shared said ‘Miss Stine’.

‘So you think she’s coming here?’ he asked, nervous.

‘I know it. I heard her on the quayside, bartering for a ride to Switzerland. I’d recognise that voice anywhere, honest I would.’

‘Did she mention Diodati?’ Mary asked.

‘She mentioned you, miss. It seems she’s carrying some sort of heavy luggage, something she wants you to see. But none of the carters would take it. They sounded scared, to be honest, and made excuses about their carts being too small, their horses too old. I reckon she’ll have had more trouble persuading people to take her – but I didn’t stay to hear the rest. I had to reach Peg before she got here. I don’t trust her, miss. Not an inch.’

‘We’d better hurry, then,’ Felix said. ‘Mary’s villa isn’t far.’

Outside, the storm was over, leaving the sky a pale, washed-out blue. The ground was soaked, the trees and bushes heavy with rainwater. By the time they’d gone through the apple orchard to the Shelleys’ villa, Felix’s stockinged legs were drenched.

As was usual at this time of day, the windows were still shuttered, even the little one where yesterday Felix had seen the child’s face. Mary guided them inside through the front door.

‘It’ll be best not to wake Percy or Claire,’ she said. ‘We don’t want a scene.’

They tiptoed through the silent house and up uneven stairs that made Lizzie stumble. Felix, gripping her arm as best he could, noticed how she trembled. Inside the attic bedroom, it was just light enough for him to see a narrow bed and a shape lying still beneath the covers.

‘Clara, dear,’ Mary said gently, going to the bed and sitting on its edge. ‘There’s someone here to see you.’

The sleeping person didn’t move.

Clara?’ Lizzie frowned.

Felix took a sharp breath: Clara was the name of Mary’s baby who’d died. At last, he began to understand why she might’ve done this, why she’d taken another child and tried to make it her own. She couldn’t save her own daughter, yet she could perhaps offer Lizzie’s troubled little sister a better life. It still seemed a strange, misguided thing to do, but perhaps it had been done in good heart.

Breaking free of Felix, Lizzie rushed towards Mary’s voice. ‘Peg! Oh, Peg!’

The shape under the covers sat up so fast it made Felix jump.

‘Lizzie? Is that you? Is Da here?’

A girl emerged from under the covers. It was hard to see her properly, for though by now Mary had opened the shutters, the bed was a tangle of arms and hair and weeping.

‘Thank goodness I found you,’ Lizzie sobbed. ‘We’ll send word to Da that you’re safe. He’ll be so, so relieved. Oh, Peg.’

Watching silently, Felix felt his throat grow thick. He hoped Mary was watching too, for, hard though this was for her, there was no doubting that these two girls were sisters. Eventually, they moved apart – Lizzie, her eyes red from crying, and Peg, whose face stretched into a grin as she noticed Felix.

‘I saw you yesterday when I looked out of my window, didn’t I? Who are you?’ she asked.

‘He’s …’

‘That’s …’

‘I’m Felix,’ he said, cutting across Mary and Lizzie. He stepped forward, hand outstretched. ‘Very pleased to meet you, Peg.’

She couldn’t take her eyes off his face. He guessed she’d never met a boy with dark skin before. Grinning still, she shook his hand so hard their arms swung, and it made them both laugh.

Mary stood a little apart from them at the window. It was the old Mary again: composed, still, quiet. But underneath it, Felix was sure her heart was breaking. He knew a little of how that felt, hoping for a future with someone only to lose them.

Letting go of Peg, he joined her in looking up at the sky.

‘The comet’s still up there,’ he observed. Today it looked even smaller and fainter.

‘And the cause of much bad fortune, so people say,’ Lizzie said from where she sat on the bed.

Felix narrowed his eyes at the sky. His mother came to mind. Back when their boat set sail for Europe she’d stood on deck and said even the stars were in their favour.

‘Look!’ she cried, pointing up at the night sky. ‘Look!’ Yet he’d seen nothing but darkness.

Today the sky was bright. The sun was coming up over the mountains; it promised to be a better day. And not just for Lizzie, who had found her sister, but for him too. These past few hours he’d done well to keep his head. Mary had listened to him, relied on him. He’d proved himself to be more than just a houseboy. If he could go to London with Lord Byron, then perhaps he wouldn’t be stared at for the colour of his skin. People would value him for who he really was and life might be very good indeed.

Mary, meanwhile, remained solemn.

‘A comet won’t decide your fortune, Lizzie,’ she said. ‘How can it? It’s just rock and ice, so the scientists say.’

Lizzie looked suddenly thoughtful. ‘Before she died, my mam laughed about comets bringing bad luck. Then all these dreadful things happened to us and I felt sure the comet was to blame. But I think maybe my mam was right after all.’

‘It looks like a star,’ Felix said.

‘A star with a tail,’ Peg added, joining them at the window.

Mary smiled weakly. ‘It’s not a star, either. Though better a star than all that mumbo-jumbo superstition people seem to believe.’

‘Maybe,’ Lizzie said, ‘it’s a strange sort of star. Not a normal-looking one but still something beautiful.’

Felix nodded. In a room of rather unusual people who, each in their own way, had beauty, he rather liked the sound of that.

‘It won’t dictate your future, however,’ Mary said. ‘That’s something only you can do.’

She was right, Felix thought to himself. The future was his to choose. He didn’t have to be a boy branded with the letter S. He was free – and capable. It was as if he’d got permission to be his very best self, instead of someone who simply met the needs of others.

From outside came the sound of an approaching horse. On the road that wound its way around the lake, a cart emerged from behind the trees. It pulled up outside Diodati. Down from it jumped a woman in a cloak, who set off through the orchard towards the Shelleys’ house.

Towards them.

‘Go!’ Mary cried, herding them out of the bedchamber. ‘It’s better that Miss Stine doesn’t see you.’

Lizzie nodded, a look of absolute fear in her face.

‘Don’t panic. You’re safe,’ Felix reassured her. ‘She can’t hurt you any more.’

Yet having heard Lizzie’s tale, he knew what this Miss Stine was capable of – experimenting on people and animals, stealing children away in the night. He didn’t exactly want to meet her, either. Better that Mary dealt with it now.

They made it as far as the top of the staircase before Miss Stine started hammering on the front door. Within moments, the entire household was awake.

‘What’s happening? Is there an emergency?’ Mr Shelley cried, appearing in his nightshirt.

Miss Clairmont rushed after him. ‘Is it Byron? Has he come calling for me?’

Pushing past Felix, Mary hurried down the stairs. ‘Percy, Claire, go back to bed. I’ll handle this.’

They went, grumbling sleepily. Mary beckoned Felix. ‘If you’re quick you can sneak out of the—’

The banging at the door became frantic.

‘Mary? I must speak to you!’ Miss Stine’s cries could clearly be heard. ‘Everything’s gone wrong!’

Frustrated, Mary threw up her hands, before disappearing down the hallway to answer the door.

Felix glanced at Lizzie.

‘You ready?’ he whispered.

She nodded. Peg looked bewildered, and suddenly very young.

‘Keep hold of your big sister’s hand,’ he said to her.

They inched down the stairs. One particular step creaked like an old ship. Felix held his breath as they passed it.

‘Which way now?’ he asked, once they reached the bottom.

‘There’s a back door,’ Peg said.

‘Come on, then,’ said Lizzie.

Peg didn’t move. ‘We can’t. It’s by the kitchens, which are …’

‘… down the hall, past the front door,’ said Felix, realising their problem.

‘Oh.’ Lizzie’s hand tightened around Peg’s. ‘Then what do we do? We can’t just stand here. If Miss Stine sees Peg she might try to take her back again. She might even …’

‘Hush!’ Felix hissed. ‘Don’t fret. We’ll have to find somewhere to hide.’

He looked around him. The hallway was long and narrow with lots of doors leading off he didn’t know where. There was no obvious hiding place. From down the hall came the click-clack of footsteps. There were voices too, quick and urgent.

‘Oh heck!’ Peg cried. ‘They’re coming!’