'No! I'll drop it.' Mrs Hagstrom was not even watching. Delphine heard the clunk of the bolt being drawn. She heard the door open. She heard a cry.

'Gah! Argh! Shut the door! Shut the door! Jesus Christ, what took you so . . . ' Pant pant. The speaker was Professor Carmichael. The clump-schlack of Mrs Hagstrom shutting and bolting the door. 'Have you seen it out there? Bats! Hundreds of 'em!' Pant pant. 'Ruddy great things, like . . . like . . . '

From the corridor behind her came the sound of smashing glass.

'Get everyone downstairs!' Delphine said. 'Get to the gun room!'

Thuds came from many directions at once. Then ticking, continuous, like hail.

Black rags flurried from the Great Hall doorways. Mrs Hagstrom fell to her knees. Creatures thumped their wings and took off, filling the space. They rose towards the domed ceiling in tight spirals like flakes of burnt paper, hissing, crackling. The Professor stared, his bristled jaw slack, his face strangely calm. Mrs Hagstrom clutched at the Professor's jumper, trying to yank him down.

Delphine gaped. The things had faces sharp, hairy faces, like pine martens', set between flared velveteen ears.

Something black and sinuous unspooled from one of the creatures as it flew. It snagged Mrs Hagstrom's thigh and began winding round her and the Professor some sort of sticky cord.

She struggled. The cord pulled tight, binding her and the Professor together, pinning their arms to their sides. The creature at the end of the line landed directly beneath Delphine.

She felt the vase slip a sudden weightlessness in her gut, as if she had fallen with it. It dropped through churning air, blasting apart on the floor.

The creature looked up.

Mrs Hagstrom hollered a single word: 'Run!'

Delphine turned. Down the corridor, a door swung open. More of the bat-dog creatures capered out, stooped and clumsy. They walked erect, skitter-hopping on taloned feet. The tips of their wings ended in long black hooks. One of them spotted her.

If she had not been drugged, perhaps she would have screamed. She ran across the landing. The air boiled with torn sou'westers caught in a tornado. She sprinted for the east wing.

A black shape swooped for her. She dived, skidding on her chest. When she glanced back, the thing was spreading its huge wings, curving steeply upwards before its feet touched down on the floor. More landed behind it. Their eyes shone like wet berries. Their wings folded and they gave chase.

She scrambled to her feet and ran into the corridor heading east, back the way she had come, the clatter-scrape of claws on floorboards close behind her. She could smell the thick, slightly musty rug beneath her feet.

What about the Professor and Mrs Hagstrom? Were they dead?

Delphine made for the long library. She had to reach the gun room. She didn't care what these beastly things were giant rabid bats, some exotic species of monkey, perhaps if she had a shotgun, she could take them down by the dozens.

No use heading there directly they'd catch her in seconds. If she made it to the library, she could slip into the hidden passage behind the bookcase and work her way downstairs undiscovered.

She could sneak from the smoking room to the green baize door northwest of the banqueting hall, with its steps leading down to the servants' quarters. She had no idea whether the hallways along the way would be swarming with . . . what had she said to Mrs Hagstrom?

Monsters.

The ground whipped from under her. Her chin bounced off the floor. She bit her tongue and cried out.

She had tripped on a ruck in the carpet. When she glanced back the creatures were coming. What she had taken for smooth torsos were quilted leather jackets worn over serge trousers cut off at the knee. They were wearing clothes. The fur on their faces flashed bronze in the electric light, their teeth like chips of glass. She pedalled her legs and started to crawl backwards but she was too slow and they were almost upon her and the frontrunner spread its horrible ripped-bodice wings and she raised her arms to shield her face.

A patch of light spread between her and the monsters. A door had opened inwards. Standing in the doorway was Dr Lansley.

'Up now!'

He stepped out into the hallway. In his right glove he held a heavy brass poker, the end decorated with several vicious flukes, like a grapnel.

The bat-monsters hesitated.

Lansley steamed into them with an underarm tennis swing, embedding the poker's spiked tip in the throat of the leader, lifting it off the floor. He pivoted and dashed its head against the wall.

Its three fellows skittered backwards. Lansley wrenched the poker from the convulsing body. Purple blood flecked the wallpaper like rain shaken from a brolly.

He turned to her. 'What are you waiting for? Move!'

Delphine scrambled to get up, slipped. Lansley grabbed her arm and yanked her to her feet. There were more creatures clattering down the corridor.

He dragged her into the room, slammed the door and slid a bolt across.

A bang sounded from the other side. Another.

She was in the chimera room. She saw her own pink face reflected in a multitude of glass cabinets. Her hair was heaped up on one side of her scalp and her chin was grazed. She winked. The battered girl in the reflection winked back.

In the centre of the windowless room stood Dr Lansley, dark blood soaking the sleeve of his tweed hunting coat. He was panting and shaking. In a corner, standing over a wheelchair with his back to her, was Mr Propp.

Propp turned slowly. His face was sunken and pale.

Delphine glanced at the wheelchair and saw that it contained not Lord Alderberen but the old lady with the bare scalp and fine white cowlick; the old lady she had watched sleep so many times. Under other circumstances, she might have felt surprise.

The old woman had a loose knitted woollen blanket draped over her legs. Her eyes were half-open but she was staring vacantly into the middle distance. Her lips were parted; her chin gleamed wetly.

Lansley's breaths worked up to a crescendo.

'Well, they picked a bloody good time, didn't they?' he screamed, swiping at the air with his poker. Little spots of congealing blood studded the floorboards. 'Fine, you said! Don't worry, you said!' For a moment, Delphine thought he was going to strike Propp.

His arm went slack.

'What's going on?' she said.

Lansley glanced back at her over his shoulder. 'Are you going to tell her what's happening, then? What you've done?'

Propp sighed with his whole body. He slipped a rough hand into the pocket of his waistcoat. He ran a finger across the length of his moustache.

'Dr Lansley is right. I am at fault.'

'Oh, that's bloody big of you,' said Lansley. 'That's bloody magnanimous.'

Two sharp bangs rattled the door.

'In truth, I am not sure how this has happened. For now it is enough for you to know it is not these creatures you should fear but their masters.'

The clicking noise was building, like a carpet of insects frothing over a jungle floor.

'Professor Carmichael and Mrs Hagstrom are out in the Great Hall,' said Delphine.

Propp looked grave. 'Then I fear they are beyond our help.'

'Where is everybody?' she said.

Propp shook his head. 'I do not know.'

'Where's Mother?' She tried to feel panic, or love. 'Where's Daddy?'

'I do not know. I am sorry.'

Lansley rushed at her, reaching into his pocket. She raised her arms to defend herself. Something clattered to the floor at her feet.

'Not much, but better than nothing,' he said.

She looked down. It was her pocket knife. She went to pick it up but Lansley dropped and snatched it and the point was at her throat. He met her gaze. He was so close she could see the thick brown fibres in his irises.

'One stroke,' he said. She felt a breeze as he flicked the blade from left to right. 'Snick. Across the windpipe.' He turned the knife round in his hand, closed his leather-gloved fingers over the blade. He held it out. Delphine grasped the handle. Lansley did not let go. He took a couple of very deep breaths, huffing and puffing like someone lowering himself into a hot bath. He looked at her. 'If you're going to use a knife, don't wave it around like a feather duster. Go for their throats. Remember. One stroke.'

He released the blade and walked away. She saw the seam of his hunting jacket on his unguarded back, felt the knife in her hand.

Lansley went back to passing the poker from palm to palm. He spoke to his reflection in the glass cabinet.

'In a moment, Mr Propp and I will distract the vesperi in the hallway. I suggest that you use that opportunity to attempt an escape. If you stay, you will certainly die.'

She glanced at the door. The popping was rising to a crescendo.

'Those things . . . are they from Hell?'

Lansley sniffed. 'Not as you understand it.'

'Where, then?'

Propp reached beneath his coat and slid the revolver from its holster. Delphine started at the drawn weapon, took a step back. Lansley was pacing.

'We must haste,' said Propp. He broke the barrel and began chambering rounds. His hands were shaking. His fingers slipped and a cartridge rolled across the floor. Delphine stooped and picked it up. A .38 hollowpoint. Nasty. So his revolver was a Mark 4, after all.

Delphine pursed her lips. 'Dum-dum rounds.' She tossed the cartridge back to him.

The men stared at Delphine.

'We need to get to the gun room,' she said. 'We can arm ourselves.'

Propp pushed the barrel up and the stirrup lock shut with a solid click. 'We cannot stay here, this is true. We leave now or not at all.'

Lansley weighed the poker in his fist. 'We'd never make it. Besides, Mrs Hagstrom has the only key.'

'I've got one.' Both men gawked at her. 'I've got keys to most of the rooms. I made copies.'

Propp smoothed his white moustache.

'So. In this case I must entrust you with great responsibility.' He walked across the little beef-paste-coloured rug to the old lady in the wheelchair. 'Take her. Get her away from house.' Then, apparently seeing Delphine's confusion, he added: 'She is my sister.'

'Are you out of your mind?' said Lansley. 'It'll be hard enough escaping alone. You can't ask her to drag a wheelchair as well.'

'So perhaps you think we should surrender? Hand child over?'

Delphine's chest froze.

Lansley glanced from the old lady to Delphine. He shook his head.

'Damn your eyes. You were right all along, pompous oaf that you are. We can't negotiate. They're animals.'

Propp turned to Delphine with those huge grey eyes. Propp the Bolshevik. Propp the deceiver.

'Will you help?' he said.

Delphine looked at Propp's sister in the wheelchair, pale and limp as a burst chrysalis. Her feet were propped on the wooden footrests inside mustard-coloured socks.

Bangs shook the door. It sounded as if the creatures had Lansley called them 'vesperi'? had found something to use as a battering ram. The bolt was barely finger-width; already the screws were working loose. A few more blows and it would give.

'What about my parents?' she said. 'What about everyone else?'

Propp and Lansley exchanged a look.

'We will do our best to find them,' said Propp. 'Perhaps they flee already. But if you do not escape, everyone in house will die, I think.'

'Why?'

'Because vesperi will have what they came for. Once that is so, they gain nothing by letting us live.'

'What are they?'

'Beasts,' said Lansley, blinking rapidly. 'Quick, tenacious. Some understand English. No real intelligence to speak of, but a rudimentary, savage cunning. Poor discipline. Given to cowardice. Beasts.'

'I think . . . I think one attacked me in the woods once.'

'What? When?'

'Just after Easter. It chased me.'

'I knew it!' said Lansley. 'They've been watching us for months! Why the Hell didn't you say something?'

'I did! No one bloody listened!'

BANG.

The wood round the bolt splintered.

'Look,' Lansley said, 'we don't have time for this. You're right,' he was talking to Delphine, 'the gun room is our only hope. With weapons, we can bed in, hold them at bay.'