And then she ran, leaving Luke standing like a fool, his arms empty, the stable his own domain again.

Rosa flung herself on to her bed, her face burning with a mix of anger and shame and something else, something that made her writhe into the pillows, unable to believe what she’d done.

What had she been thinking? Sobbing on the shoulder of a stable-hand! Thank God no one had seen. And he – what had he been thinking? If Alexis or her mother had seen them, she would have been whipped and Luke would have been sacked for gross impertinence, and it would be no more than he deserved, putting his arms around her as if – as if . . .

And yet, as Rosa’s face cooled, she thought that perhaps it wasn’t that, not really. There had been nothing impertinent about his expression as he looked down at her, nor about the way his hand had rested on the nape of her neck, on the tender slip of skin between her riding stock and her hair. It was as if . . . it was as if he thought for a moment they might have been – friends.

He wasn’t a servant, of course. At least, not in the sense that Fred Welling or James were. They were born and bred to it, trained to service from their childhood. From what Ellen had said Luke was the son of a drayman, expected to become a drayman like his father, mixing only with others of his class and sphere and never thinking to so much as speak to a lady from one year’s end to another. So perhaps it was no wonder that he wasn’t used to mixing with his betters and acted so strangely ignorant of the gulf that separated them both.

Rosa had no such excuse. She knew every inch of the great social chasm that yawned between them. And, too, she knew what he did not, could not. For they were separated by more than class, by a gulf just as unbridgeable: magic.

That at least, she reflected, as she flung herself on to her back and put her pillow over her cooling face, was one comfort. If he ever showed any signs of getting above himself or taking liberties, she could sort him out with a few words of a spell, as Alexis had done with Becky time and time again. A few kisses on the landing, a few squeezes in the library, and the girl was batting her eyelashes over the morning tea and making veiled threats about presents and payrises. Each time it happened she sealed her own doom and the next day she would be clearing at breakfast just as blank and respectful as if the whole thing had never happened – which indeed, as far as she was concerned, it had not.

The thought of Alexis was like a splash of cold water. He would be angry, very angry. And he would want her to make it up to Sebastian. The only question was how.

‘Is this true, Rosa?’ Mama looked from Rosa to Alexis and back again. They were waiting in the drawing room, where Rosa had been summoned to give an account of her actions. Mama was sitting on the chaise longue, her needlepoint spread across her lap, and the needle stabbed in and out of the silk as if she were stabbing an enemy.

‘Well?’ Alexis turned from where he was warming himself in front of the glowing remains of the fire and smoothed down his coat tails. ‘Cat got your tongue, Rosa? Or should I say, dog?’

Rosa’s hand crept nervously to her locket and then she snatched it away, before Alexis had time to notice. Instead she picked up Belle, who was shadowing anxiously at her heels as if she sensed the gathering storm.

‘Yes,’ she said. She was proud of the way her voice was steady, in spite of Alexis’ barely contained fury and Mama’s smouldering anger. ‘Yes, it’s true.’

‘You are telling me . . .’ Mama’s voice was dangerously low and she stabbed the needle into the hoop with a violence that made Rosa wince. ‘You are telling me, that you stood in Hyde Park and screamed at Sebastian Knyvet like a fishwife, berating him for beating his own dog in your defence? And for this you dared call him a brute?’

‘Yes.’ Rosa made herself stand straight. Belle cowered against her shoulder.

Mama turned to Alexis and some silent communication passed between them, Rosa could see the flicker of it in their eyes. She turned away deliberately. Let them have their magical whispers. If they were too ashamed to say the words in front of her, she didn’t want to hear them anyway.

‘Rosa.’ Mama’s voice broke in on her thoughts. ‘We have not finished with this. For tonight you will go to bed without any supper. Tomorrow you will get up without any breakfast. However you will ride out, you will meet with and speak to Mr Knyvet and you will apologize to him for your disgraceful behaviour. Is that quite understood?’

‘But—’ Rosa began. Mama hissed the words of a spell and Rosa’s throat suddenly tightened and closed. The words she had been about to speak strangled before they reached her lips. Only when she tried again did two misshapen, mangled sounds come out: ‘Yes, Mama.’

‘Good.’ Mama’s lips smiled, but her eyes were still cold and angry. ‘Now, listen to me, Rosa. Sebastian has the power in the palm of his hand to repair our fortune, to secure Alexis’ future and to save your family home, and you throw all that away over a disobedient dog and your own love of histrionics. What do you think Papa would think of your abominable selfishness?’

Rosa shut her eyes. She would not cry. Not in front of Mama.

‘The mortgages are up on Matchenham in two months.’ Mama picked up a sheaf of papers from the desk and threw them at Rosa’s feet. ‘Two months. If you wish to see your father’s home sold to the highest bidder then you are going the right way about it. Now, go to your room. I do not wish to see you again tonight, do you understand?’

Any words of protest died in Rosa’s throat. Instead she just nodded. Then she turned and left, still holding Belle. As she climbed the stairs to her room she felt the first stirrings of hunger in the pit of her stomach.

It was nearly midnight before Luke finished grooming the horses and cleaning the tack. Late in the evening Alexis had sent word downstairs that he and Rosa would be riding again tomorrow, and that the horses were to be immaculate, and the tack and brasswork too.

When Luke finally made it up the stairs to his little room, he lay on the hard, narrow bed with his arm flung over his face as if to hide from the world. What had he been thinking, there in the stable? He’d risked everything – and for what? To comfort a girl who was his mortal enemy, who would be dead at his hand within a few days. And instead of plotting her death, he’d risked his job and his mission to comfort her over the death of a worthless pup.

For God’s sake, lad, what’s wrong with you?

It was John Leadingham’s accusing voice that rang in his ears. But it was William’s face he saw when he squeezed his lids tight shut – William’s face, filled with disgust and grief at his betrayal.

Suddenly he couldn’t bear his own thoughts any longer. He sat up and walked to the window, as if the cold night air could chase away his hot shame. He leant on the sill, resting his forehead against the breath-misted glass, and stared into the night. Knightsbridge was not like Spitalfields. Instead of the dark, crowded slums punctuated with burning street braziers, it was bright with gas street lights, there were candles at every window, stretching away and away into the distance, even the odd house that blazed with electric light. He looked up, above the roofs, hoping to see the stars. They at least would be proof that however far away home felt, he walked under the same skies as William and Minna and John and all the other friends he’d left behind. But the night was dark, with thick sooty clouds that shut out the sky.

He sighed and was about to turn to go to bed when a movement at the window across the yard caught his eye. A window was alight in the big house. It was lit with a single candle, and someone was sitting there, staring into the darkness. In the soft candlelight all he could see was a face and a flicker of white nightgown. But as the figure moved slightly he saw the blazing river of hair that fell to her waist, a stream of molten iron that caught the light of the frail candle flame and threw it back as fire.

Rosa.

No, God damn her, not Rosa. The witch. He must stop thinking of her as a girl, for she was not a girl. She was a witch – damned in the sight of God and condemned by man and by the word of the Bible. Condemned to—

The breath caught in his throat and he wrenched his gaze away from her and threw himself back into his hard narrow bed, his fists clenched in cold self-hatred.

She must die. That was all there was to it. He had pricked her name with his pin – fate had chosen her, not him. If he didn’t return of news of her death within the month then it would be his blood spilt, not hers.

Within the month. How long, exactly? Luke began to count back to the night in Fournier Street, and his heart became colder and colder with each backward step. It was more than a week ago, ten days, in fact. He had just eighteen days left. Eighteen days to kill her and return with the news to the Brotherhood.

But he didn’t need eighteen days. It only took a moment to kill – he just needed an opportunity. A plan that would not leave him swinging from the gallows or gutted by a spell.

And suddenly a way of doing it came into his head – and it was so simple he could have almost laughed. Only, it all depended on whether she would ride out tomorrow to meet Sebastian Knyvet. Would she?

Luke slept badly that night, torn between thinking of all the ways that his plan could go wrong and the chance that it would not happen at all. Would she really ride out to meet Knyvet, after all that had happened yesterday?

But the message came down after breakfast: Cherry and Brimstone to be saddled and ready in ten minutes, Mr Greenwood’s orders.

He took a deep breath and made his way out to the stables.

He’d only just finished saddling Brimstone when he heard the sound of boots on the cobbles and looked up to see Alexis striding across the yard, Rosa walking behind him, her face white and pale.

‘Is Brimstone ready?’ Alexis demanded. Luke nodded.

‘Yes, sir. But not Cherry, I’ve still got to saddle her up.’

‘Dammit, I said ten minutes. Seb’ll be waiting.’

‘I’m sorry, sir,’ Luke tried to keep his face impassive. He bit back the words he really wanted to say: You try grooming and saddling two horses in ten minutes, you fat slob.

‘Well, I’m not waiting on the convenience of a lazy stable-hand.’ He swung his leg up and called, ‘Rosa, I’m heading out. Come and find me with the boy. I’ll be near the north end, I suppose. Don’t take all day.’

Rosa said nothing but only nodded.

‘Cat got your tongue?’ Alexis said, and there was something unpleasant in his voice, a needling laugh.

Rosa looked up at him and her gold-brown eyes were suddenly dark with hatred, her lips pressed together until they were completely bloodless. Her whole face, white beneath the stark black hat, seemed nothing but blazing eyes, full of fury. But she said nothing, only jerked her head towards the gate.

‘See you in the Row,’ Alexis said. ‘I’ll leave you with the sot.’ And with that he yanked on Brimstone’s curb and nudged him into a canter out of the yard and down the mews.

As the sound of Brimstone’s hooves faded into the distance Rosa let out a shaky breath and seemed to find her voice.

‘I’m sorry.’ Her voice was hoarse, as if she hadn’t spoken in a long time. ‘He shouldn’t be so rude to you – it’s unforgiveable.’

‘Me?’ Luke said surprised. ‘I don’t give a d—’ He stopped himself short, just in time and bit back the word. ‘I don’t mind what he chooses to call me,’ he finished gruffly.

She didn’t answer, but just sank on to a hay bale while he adjusted the buckles. His fingers were sweating and his heart was beating fast – this was the moment. If she looked up now, he was sunk. His fingers slipped on the cold metal of the buckle. But she didn’t. Her head was bowed between her knees, almost as if she were faint, and she was not looking at him or Cherry, but down at the voluminous folds of her jet-black habit.

It was done. He patted Cherry’s side, feeling his flesh prickle cold and hot with sweat. Then he turned to Rosa.

‘Ready, Miss Greenwood,’ he said. Then he stopped awkwardly. ‘Is something wrong?’

‘I – I missed breakfast,’ she said wearily.

Luke looked down at himself, then brushed the straw from his britches.

‘Wait here.’

Becky was folding linen when Luke put his head cautiously round the kitchen door and whispered, ‘Hey. Hey – Becky.’