‘Sorry, Knyvet,’ Alexis was saying. ‘New stableboy. Our usual chap broke his arm and got himself laid up for a month, so we’ve got his sot of a cousin filling in.’

‘He’s not a sot, Alex,’ Rosa said stiffly. ‘He’s just new. Give him a chance. Anyway, Mr Knyvet doesn’t want to hear our domestic troubles, do you, sir?’

‘Au contraire.’ The man bent over Rosa’s hand, his horse stamping and sidling as he kissed her gloved knuckles. ‘Everything about you is charming to me, Miss Greenwood. What a delightful . . . surprise to see you both here.’

‘Oh . . .’ Luke saw a flush on Rosa’s cheek. ‘As Mama said, I – I love to ride.’

‘I remember that from Matchenham. Although, as I recall,’ he looked at her from beneath his lashes, his blue eyes veiled and lazy, ‘as a little girl you were happier bareback. But what I meant was, what brings you to the Row? I’ve never seen you before.’ There was something in his expression that Luke couldn’t quite place, something teasing, speculative, not quite pleasant, as if Rosa were a moth beneath a pin and he was not going to let her go easily.

‘I don’t think Mama would permit me to ride bareback these days,’ Rosa said lightly, skirting his question, although the flush remained on her cheek, high and angry. The man, Knyvet, smiled, and was about to say something when his dog leapt up exuberantly at Rosa’s skirts.

‘Down, Pointer!’ Knyvet snapped, and he kicked the little dog with his shining boot, sending it tumbling over the rutted surface of the row.

‘Sebastian!’ Rosa cried, and the little creature whimpered with pain and cowered back at its master’s heel.

‘Oh don’t mind Rosa,’ Alexis said with a sneering laugh. ‘Her heart bleeds for anything on four legs. She’s not quite so bothered about the chaps on two.’

‘I’ve no use for disobedience,’ Knyvet said. ‘Be it in dogs, horses or servants. If they cannot learn to obey of their own volition they must have it beaten into them.’ Then he gave a short laugh. ‘But enough of this; let’s speak of lighter things. Since we’ve met so serendipitously’ – a smile creased his cheek – ‘won’t you allow me to escort you across the park? I’m on my way to the headquarters, so our paths lie in the same direction.’

‘I’d be delighted,’ Rosa said slowly. Her eyes went back to the little dog trotting in Knyvet’s shadow, its tail firmly between its legs.

As they set off, Alexis hung back.

‘Don’t wait for me,’ he called. ‘I’ve a fancy Brimstone’s limping. I’ll get the boy to take a look at his shoe and catch you up.’

Obediently Luke slid from Castor and pulled up the leg Alexis indicated with his whip. It looked sound enough. The shoe was firm and there was no swelling and no stone in the hoof, or none that he could see.

‘I can’t see nothing, sir,’ he said. ‘Do you want me to check the other leg?’

‘Of course not, there’s nothing wrong, you fool.’ Alexis’ voice was low and full of contempt. ‘Just dig at it with your knife or whatever you do. Make it look realistic and try not to be more of an idiot than your mother made you.’

Luke gritted his teeth and drew out his pick, pretending to pull out an imaginary stone from Brimstone’s shoe, but all the while following Rosa and Knyvet with his eyes. They rode like a matched pair, as they trotted down the Row, Rosa so slim and straight in her black habit that it looked as if he could break her in two, Knyvet tall and erect in the saddle beside her, his top hat making him look even taller, their magic crackling around them both like a cloud of light and storm. So this was the plan, was it? Marry her off to the tall arrogant bastard of a witch, to create more witch babies to wreak more misery on the world? Well, not if he could help it.

His fingers tightened unconsciously on the pick and Brimstone gave a whinny and flinched, pulling his foot away from Luke’s grip.

‘Hi, you fool!’ Alexis snapped. ‘You don’t need to carve the poor brute’s hoof out. Make it look realistic, I said, not stick him to the quick.’

‘Sorry, sir,’ Luke muttered. He stood, shading his eyes, watching Knyvet leaning into Rosa, saying something close to her ear. She laughed at his remark, her magic shimmering like a halo of ghostly fire in the winter sunlight.

‘Come on,’ Alexis said impatiently. ‘We’ve given ’em long enough. Any more and it’ll start to look obvious.’

Luke swung himself back into the saddle and they both cantered down the last length of the Row, to where Kynvet and Rosa had stopped beneath a tree. As they came up the last few yards separating them, Rosa laughed again and said something to the little dog, putting her hand down towards it. It yipped out a bark, jumping joyfully towards her hand, and then leapt back towards Knyvet. He kicked it away and it gave a whine. Knyvet said something to Rosa and she shook her head and clicked to Cherry, but as she did the pup leapt up again. There was an ominous rending sound and Rosa gave a cry.

‘Dammit, Rose!’ Alexis pointed with his crop at the hanging triangle of black fabric. ‘The brute’s torn your skirt!’

‘It’s nothing,’ Rosa said quickly. She bent, pressing her handkerchief to her calf, and Luke saw, with a feeling of foreboding, that it came away red.

‘God-damn it.’ Knyvet flung down his reins. The little dog wagged its tail joyfully at the sight of his master dismounting, but then Knyvet grabbed its collar and it squealed in pain. He picked up his riding crop.

‘Sebastian!’ Rosa cried. He ignored her and lifted the whip, and the little dog screamed as it came smacking down. He lifted it again, and again it bit, and the pup let out a squealing wail. Luke turned his face away.

‘Sebastian!’ Rosa shouted. There was a scrambling sound and Luke turned back to see her slide from the pommel of the side-saddle in an ungainly slither. She fell to her hands and knees on the ground but scrambled up. ‘Sebastian, stop! For God’s sake, stop!’

Knyvet didn’t seem to have even heard. He was labouring the little dog again and again with all his strength. The creature had stopped crying and lay limp in his grip, only the force of Knyvet’s blows making its body jerk.

‘Sebastian!’ Rosa sobbed. She grabbed at his arm, but he threw her off without even turning his head and she staggered back.

Luke swallowed. His fists were clenched. He felt a fierce desire to grab Knyvet by the collar and beat him like he was beating the dog, beat him until he squealed like the defenceless pup. But it would be suicide to strike a witch and, worse, suicide to his mission. He would be sacked, thrown from the house, and then where would he be? He had barely three weeks left – there would be no time for another plan, no time to do anything but crawl back with his tail between his legs. And then he would be dead himself, at the hand of the Malleus, as all men were who failed in their task.

‘Sebastian!’ Rosa’s voice was hoarse and cracked on the last syllable of his name. ‘Please.’

Luke’s hands were clenched on the reins so that the tendons stood out. He concentrated on his hands, on the burns and smelts left there by years of work in the forge. Concentrated on holding in Castor, holding him steady, when all he wanted to do was turn the horse for home and gallop far away from this place.

At last the sound of thrashing ceased and, in the silence that followed, he heard Rosa’s low sobbing breath. Sebastian seemed to hear it too, for he looked up, his face splashed with blood, but impassive. His eyes were very blue, the cold pale blue of the winter sky above.

‘For God’s sake, Rosa,’ he said. ‘It was only a dog – and a damned disobedient one at that.’ And then he kicked the corpse into the bushes at the side of the Row and mounted his horse in one swing, his spurs flashing in the sun.

‘Good day to you both.’ His voice was quite level and pleasant. Only the rise and fall of his chest and the flecks of blood across his cheekbones and the bridge of his nose betrayed what he’d just done. ‘Miss Greenwood, please allow me to apologize for the damage to your habit.’ He gave a bow, raised his top hat and then turned to Alexis. ‘Alex, shall I see you at Raffles tonight?’

‘Certainly,’ Alexis said. He raised his own hat and Sebastian cantered off.

Luke watched him go, disappearing into the throng of well-dressed ladies and men, his magic a pitch-black swirl of smoke dispersing into the bright sunshine and red-gold leaves of the autumn trees.

He was still staring after Knyvet’s departing shadow when he heard Alexis’ voice behind him.

‘Come on, Rose, for God’s sake. Get up and stop acting like a Shakespearean tragedy. It was only a dog.’

Luke turned. Rosa was sitting, collapsed against the tree trunk, her face in her hands. When she raised her eyes they were filled with grief and bitter accusation.

‘Look,’ Alexis said uncomfortably, ‘I’m not saying he was right to beat it but—’

‘He whipped it to death, Alex. In the park.’

‘It ripped your skirt! Look, a disobedient dog is a recipe for disaster. You can never eradicate bad blood. A dog who won’t obey commands has only itself to blame. Next it would have been going after sheep and snapping at children. Seb had no choice.’

‘He had a choice,’ Rosa said. Her voice was cold and bitter. ‘Of course he had a choice.’

‘Rose!’ Alexis said, his voice impatient. ‘It was a dog. A dog. What do you want? Black ostrich plumes and a hearse? Get back on Cherry and stop acting like he beat your first-born child to death.’

‘I will not.’ Rosa’s voice shook. Alexis’ lip curled in contempt.

‘Suit yourself.’ He kicked at Brimstone’s flanks and yanked the horse’s head viciously around. ‘I’m going.’