The thought lifted her spirits. She sped up, even allowed herself to entertain fantasies of a search party scouring the grounds mere feet above her head, thrashing through the bracken with golf clubs and walking sticks. After a few minutes, she was starting to enjoy herself. She came to a T-junction.

One passage led left, the other right. She called down both.

'Hello? Hello?'

Nothing.

Delphine dithered, her optimism draining. She unpopped her cardigan and placed Maxim and Lewis on the floor. Ferrets were bred to burrow underground then find their way back again. Whichever way they chose was surely the road to freedom.

Squinting through the darkness, she watched the two ferrets knot their bodies together and settle down to nap.

'Useless!' She rubbed their backs vigorously, trying to chivvy them into action. 'Come on! Which way?'

It was no good. The ferrets had woven themselves into a chubby pretzel of indolence.

She was starting to feel hysterical. She cried for help, and the low echo made her feel as if the walls were closing in. Her air was running out. She definitely felt lightheaded. Maybe the rabies virus was seizing hold of her wits. It was an horrendous way to die, frothing, baffled, enraged.

She considered praying, then worried it might make God angry. She hadn't prayed for months, not since school to do so now might draw His attention and remind Him that her spiritual account was in arrears.

With every moment she hesitated, the air seemed to get thinner, her mind weaker. She had to decide.

'Eeny meeny miny moe . . . ' The pendulum of her forefinger settled on the path to the left.

She grabbed Lewis and Max and marched down it before she could change her mind. The tunnel narrowed, curving right. Her sandals splashed through puddles. The thrill of committing herself had set her heart galloping, so she was oddly disappointed when the tunnel ended and her fingers closed around the rung of a metal ladder.

She shook it. The ladder held firm.

Delphine buttoned the ferrets inside her cardigan to leave her hands free. She climbed in short stages, resting in between, allowing her injured foot to hang. Very soon, she reached a ceiling. She pressed a palm against it. It was wood.

Delphine pushed. The ceiling held firm. The light had improved to such an extent that she could see her hand. She felt around. Heavy oak boards. She slapped the wood then, hooking her wrist round a rung, balled her other hand into a fist and pounded the barrier above her. Each blow boomed there was space above. She was below a floor somewhere. If the boards had been rotten, perhaps she could have punched through, but they felt dry and sturdy. She thumped them again and again, beating her knuckles raw, punishing herself for her lack of preparation, for picking the wrong path, for not knowing the things to say to get grown-ups to listen to her, for Wait. She froze. Her fist crumpled, shaking. She listened.

There it was again. Noises from above. Movement.

Delphine beat against the oak for all she was worth, and was sucking in air to bellow for help when the roof lifted cleanly away, a hinged trapdoor, and a blast of light turned everything orange-white. She blinked, shielded her eyes.

The first thing she saw was the gun.

'I expect the Hall is in uproar,' she told Mr Garforth, bathing her cuts by the warmth of the fire. 'I expect they've sent out a search party.'

The old man did not look up. 'Well, then you'd bestn't stay for cocoa.'

'Oh, well I'm sure five minutes won't make a difference.' She winced at the sting of the washcloth. 'Since I'm here.'

Mr Garforth rolled his eyes. The table was covered with gun parts from a pre-war Belgian hammerless that he was struggling to re-assemble. He took a jug from the countertop and poured milk into a saucepan.

'You're an idiot,' he said, 'by the way.'

'You're lucky I wasn't killed.'

'I'm lucky?'

'You must've known it'd break sooner or later, a flimsy bit of board.'

He set the saucepan on the stove. 'I didn't think anyone'd be so stupid as to go jumping up and down on it.'

'I didn't jump, I fell.'

'There you go,' he said. 'An idiot.'

Delphine dropped the washcloth back into the bucket and pulled on her long cotton socks.

'I think I have rabies.'

'There's been no rabies in England for years.'

'A bat chased me.'

Mr Garforth looked back over his sloping shoulder. 'What are you talking about?'

'A bat. In the woods. It was huge.'

He stared at her for a long time. 'A bat.'

'It chased me all the way down the hill. I thought I was going to die.'

Mr Garforth lowered his head. He narrowed his eyes and his whiskers moved to the rise and fall of his chest. The cottage filled with hissing and spluttering. He swore and returned to the foaming pan of milk.

Delphine watched his back. Through his shirt, his shoulder blades formed a dark chevron.

'What is it, anyway?' she said.

'What's what?'

'The place I fell into.'

'What do you mean, "What is it"? It's a bloody great hole, what d'you think it is?'

'All right.' She took a breath. 'I suppose what I really mean is why is it? Why is there a tunnel going all the way to your cottage?'

Mr Garforth stirred the milk faster. 'No idea.'

'Don't tease.'

'I'm not teasing. The master's father built them before I arrived.'

She sat up sharply. 'There are more?'

'They go all over the estate. Well, those where the roof hasn't caved in.'

'Gosh.'

'That's not an invitation to go exploring. They haven't been used for years. They're very dangerous.'

'Of course.'

Delphine gazed at the uneven black and terracotta floor tiles, tracing the repeating diamond design with her eyes as if it were a maze. Several tiles were missing, creating dead ends from which she had to backtrack.

'I wouldn't want to, anyway,' she said. 'They were full of horrible insects.'

'Eh?'

'You know creepy-crawlies. I felt them on my face while I was coming round.'

'You dreamt 'em.' Mr Garforth appeared at her shoulder with a steaming mug. 'Don't spill it.'

She lifted it to her lips.

'And don't burn yourself,' he added.

Delphine blew. She looked from her cocoa, to the maze, then to Mr Garforth.

She said: 'Was Lord Alderberen's father mad?'

Mr Garforth set his mug on the table and sat with a grunt. He picked up a screw.

'Who told you that?'

Delphine shrugged.

Mr Garforth tried the screw in the top of the buttplate. After a couple of twists, it popped from his fingers. He swore, then groped around until his hand settled on a screwdriver.

'I never knew him,' said Mr Garforth, a bit too loud, 'but as I understand it, his only crime was wanting a bit of peace and quiet. If that's what passes for madness these days then argh, damn it all!' The head of the screwdriver slipped and scored an ugly line across the walnut gun stock, while the screw pinged loose and rolled off the table.

Delphine put her cocoa down by the fire, walked over and retrieved the screw. She held it up to her eyes, as if she were a giant clutching a tiny, naughty man.

'Do you want me to have a go?'

Mr Garforth glowered. 'Give me that.' He moved to snatch the screw; she pulled her hand back. 'Stop fooling around.' Delphine hesitated. She placed the screw on the table.

She watched as he tried for a third time to fit it into the buttplate. A tremor worked its way from his hand, through the screwdriver and into the screw, which rattled testily. He tightened his grip; the shaking increased. He slammed the screwdriver down.

'Useless! It's rusted to bits.'

Delphine nodded gravely. Mr Garforth ploughed his fingers through the final greasy strands of his hair.

'Um . . . since it's broken, can I have a look? You know . . . just to see?'

Mr Garforth pinched his nostrils, tapping the bridge of his nose with his forefinger. He stared at the dark window. He pushed his chair back.

'Do whatever you want.' He picked up his cocoa and walked to the fire.

Delphine waited, then took Mr Garforth's place at the table. Sitting hurt. The chair was still warm. She picked up the screw and examined it. The thread was a little worn at the tip, but otherwise it looked fine. She glanced over her shoulder at Mr Garforth. He was sitting with his back to her, watching little purple flames claw at a new log.

Lining up the holes on the buttplate and stock, she slotted the screw into position then took the screwdriver and began to twist. The screw rotated in place, refusing to bite. She pushed; the black bruise on her tricep sang. The screw yielded; three more turns and it sat snugly in the plate. Delphine sorted through the bits till she found the second screw. Once she had twisted it into the base of the stock, she turned to Mr Garforth.

'I've done it.'

He did not look up from his bible.

She held up the gun butt, polished iron scrollwork flashing in the firelight. 'Hey, look. I did it.'

Mr Garforth put a finger to his lips. As the finger lowered, she saw his lips were moving, silently reciting. She watched for a moment, then felt a little embarrassed and turned back to the table.

Over the next fifteen minutes, Delphine rebuilt the shotgun piece by piece. Pain left her, utterly. Her mind was empty as a jug. When she was finished, she took it from the table, heavy and whole. She looked down the breech then shut the gun with a sure, true click.

A hand gripped her shoulder.

'Good.'

She looked up. Mr Garforth nodded.

'They don't make 'em like that any more,' he said. He stepped round the table and pulled out the second chair. 'Simple. Reliable. No fancy business to clog or wear out.'

'I like it.' She held it out for him.

'It's yours.'

She nearly dropped it. She blinked and wobbled.

'No.'

'Well, if you don't want it '

'No, no I do, it's just . . . ' She put the 12-bore down on the table. Her hands felt too light without it. She looked at Mr Garforth. 'I don't understand.'

'Not yet you don't.' He set the bible down, next to the gun. His quiet time had changed him; he seemed calmer, softer. His lips formed a half-smile. 'There's one condition.'

'Go on.'

The half-smile vanished. 'Stay away from the woods for the next few days. Till I've sorted your bat problem.'

She scratched the back of her neck. 'Okay.'

'And no playing in the tunnels.'

She narrowed her eyes. 'Hey. That's two conditions.'

'I mean it. Promise me. I'll know if you've gone back on your word.'