The front of the house looked sad and blind, with light brown plywood hammered over all the windows and a heavy black tarpaulin hanging from under the roof to hide the hole in the centre. At the rear, the windows were shuttered and the bare roof rafters were covered but the devastated centre was still open to the elements. Several men in hard hats and overalls were working there, slowly picking up pieces from the huge jumble and carrying them to throw them into a rubbish skip which stood a short distance away across the lawn.

"Do they Propose to move all that by hand?" I asked.

"As much as is necessary," Yale said. "We've got a surprise for you." He waved to a man in beige overalls with a blue hard hat who came over to us and asked me my name.

"Ian Pembroke," I said obligingly.

He unzipped the front of his overalls, put a hand inside and drew out a battered navy-blue object which he held out to me with a small satisfied smile. "You may need this," he said.

Never a truer word. It was my passport.

"Where on earth did you find it?" I said, delighted.

He shrugged and pointed to the mess. "We always come across a few things unharmed. We're making a pile of them for you, but don't get your hopes up."

I zipped the passport into my new Simpson's Barbour and thought gratefully that I wouldn't have to trail around getting a new one. "Have you found any gold-and-silver-backed brushes?" I asked.

"Not so far."

"They're my father's favourite things." "We'll look out for them," he said. "Now, we'd like you to help us in return."

"Anything I can."

He was a lean, highly professional sort of man, late forties I guessed, giving an impression of army. He said his name was Smith. He was an explosives expert.

"When you first came here yesterday morning," he said, "did you smell anything?" I was surprised. I thought back. "Brick dust," I said. "The wind was stirring it up. It was in my throat."

He grunted. "This looks like a gas explosion, but you're quite certain, aren't you, that there was no gas in the house?"

"Absolutely certain."

"Do you know what cordite smells like?" he asked.

"Cordite? Like after a gun's been fired, do you mean?"

"That's right."

"Well, yes, I know what it smells like."

"And you didn't smell that here yesterday morning?"

I looked at him, puzzled. "No one was shot," I said.

He smiled briefly. "Do you know what cordite is?" he asked.

"Not really."

"It was used very commonly as a general explosive, "he said, "before Nobel invented dynamite in 1867. it's less fierce than dynamite. It's sort of high- grade gunpowder and it's still used in some types of quarries. It explodes comparatively slowly, at about two thousand five hundred metres per second, or a little over. It explodes like a gas. It doesn't punch small holes through walls like a battering ram. It's rather like an expanding balloon that knocks them flat."

I looked at the house.

"Yes, like that," Smith said.

"Cordite…" I frowned. "It means nothing."

"Its strong smell lingers," he said.

"Well… we didn't get here until ten, and the explosion was at four-thirty in the morning, and it was fairly windy, though not as rough as today. I should think any smell had blown away." I paused. "What about all the people who were here before us? What do they say?"

"They're not here today," Smith said succinctly. "I haven't asked them."

"No one said anything to me about a smell," I said.

Smith shrugged. "We'll do microscopic tests. We would do, anyway. But it looks to me as if cordite is a strong possibility."

"Can you buy cordite?" I asked vaguely. "Can anyone?"

"No, they definitely can't," Smith said with decision. "Twenty years or so ago, maybe, but not now. Since terrorism became a part of life, most sorts of explosives are highly regulated. It's extremely difficult for the general public to get hold of them. There are a few explosive substances on the open market, but detonators to set them off are not."

I found I was thinking of cordite in terms of the small quantities used in firearms, whereas to knock down half a house…

"How much cordite would that have taken?" I asked, gesturing to the results.

"I haven't yet worked it out. A good deal."

"What would it have been in?"

"Anything."

"What does it look like? Is it like jelly?"

"No, you're thinking of high-explosive TNT. That's liquid when it's fed into bomb cases, then it gels inside. Bombs dropped from aircraft are that sort. Cordite is loose grains, like gunpowder. To get a useful result, you have to compress it. Confine it. Then you need heat to start off the chemical reaction, which proceeds at such a rate that the ingredients appear to explode."

"Appear!" I said, and added hastily, "OK, I take your word for it, don't explain."

He gave me a slightly pitying look but let up on the lecture and went back to searching in the ruins. Superintendent Yale asked if any of the Pembrokes had ever had any connection whatever with quarries. None that I knew of, I said. It was most improbable.

"Or had friends who had quarries, or who worked in quarries?"

I didn't know. I'd never heard of any.

My gaze wandered away from Smith and his fellow diggers after truth, and I became more aware of the audience beyond the rope in the garden. There weren't anything like as many as the day before but clearly the work in progress was a draw in itself.

Arthur Bellbrook was there again, talking away. He must enjoy the celebrity, I thought. He'd been the one who'd found Moira, and now there was the house… Arthur was talking as if he owned the news, rocking back on his heels and sticking his stomach out. The dogs on their leads patiently waited. It didn't matter to them, I supposed, that Arthur was into maybe the twentieth account of life and death with the Pembrokes.

A stray piece of memory connected Arthur to the smell of cordite, and I couldn't think why that should be until I remembered him carrying his shotgun into the house on the day he'd thought I was a burglar.

I cast the stray thought out but it sauntered back, telling me it was nothing to do with Arthur and shotguns.

What then?

I frowned, trying to remember.

"What's the matter?" Yale said, watching me.

"Nothing, really."

"You've thought of something. One of your family DOES have a quarry connection, is that it?"

"Oh no," I half laughed. "Not that. The smell of cordite…"

The smell of cordite on a misty morning, and the gardener… not Arthur, but old Fred before him… telling us children to keep out of the way, to go right back out of the field, he didn't want our heads blown off…

I remembered abruptly, like a whole scene springing to life on a film screen. I walked across to where Smith in his hard blue hat bent to his task and said, without preamble, "Does cordite have another name?"

He straightened, with a piece of brick and plaster in his hand.

"I suppose so," he said. "It's commonly called 'black powder'."

Black powder.

"Why?" he said.

"Well, we had some here once. But long ago, when we were children. Twenty years ago at least, probably more. But I suppose… some of the family could have remembered… as I just have." Yale, who had followed me to listen, said, "Remember what?"

"There used to be four or five great old willow trees down by the stream, across the field." I pointed. "Those you can see now are only twenty years old or so. They grow very fast… they were planted after they took the old trees down. They were splendid old trees, huge, magnificent."

Yale made hurrying-up motions with his hands, as if to say the state of long-gone willows, however patrician, was immaterial.

"They were at the end of their lives," I said. "If there was a gale, huge branches would crack off. Old Fred, who was the gardener for years here before Arthur, told my father they weren't safe and they'd have to come down, so he got some foresters to come and fell them. It was dreadful seeing them come down…" I didn't think I'd tell Yale that half the family had been in tears. The trees had been friends, playground, climbing frames, deepest purple imaginary rain forests: and, afterwards, there was too much daylight and the dead bodies being sawn up for firewood and burned on bonfires. The stream hadn't looked the same when open to bright sunshine; rather ordinary, not running through dappled mysterious shade.