All physical signs of Serena had mercifully been taken away, and all that remained were the torn flaps of black plastic that hadn't been near her.

Mr Smith shook hands with us dustily and after a few commiserating platitudes came out with his true opinions.

"Anyone who carries a fully-wired explosive device from place to place is raving mad. You don't connect the battery until the device is where you want it to go off. If you're me, you don't insert the detonator, either. You keep them separate."

"I don't suppose she meant to drop it," I said.

"Mind you, she was also unlucky," Mr Smith said judiciously. "It is possible, but I myself wouldn't risk it, to drop ANFO with a detonator in it and have it not explode. But maybe dropping it caused the clock wires to touch."

"Have you found the clock?" I asked.

"Patience," he said, and went back to looking.

A policeman fending away a few sensation seekers told us that Superintendent Yale had been detained, and couldn't meet us there: please would we go to the police station. We went, and found him in his office.

He shook hands. He offered sympathy.

He asked if we knew why Serena had gone to Quantum with a second bomb, and we told him. Asked if we knew why she should have killed Moira and tried to kill Malcolm. We told him my theories. He listened broodingly.

"There will be an inquest," he said. "Mr Ian can formally identify the remains. You won't need to see them… her… again, though. The coroner's verdict will be death by misadventure, I've no doubt. You may be needed to give an account of what happened. You'll be informed of all that in due course." He paused. "Yesterday, we went to Miss Pembroke's flat and conducted a search. We found a few items of interest. I am going to show you some objects and I'd be glad if you'd say whether you can identify them or not."

He reached into a carton very like the one Serena had been carrying, which stood on his desk. He brought out a pile of twenty or thirty exercise books with spiral bindings and blue covers, and after that a tin large enough to contain a pound of sweets, with a picture on top.

"The Old Curiosity Shop," Malcolm said sadly.

"No possibility of doubt," Yale nodded. The title's printed across the bottom of the picture."

"Are there any detonators in it?" I asked.

"No, just cotton wool. Mr Smith wonders if she used more than one detonator for each bomb, just to make sure. He says amateurs are mad enough to try anything."

I picked up one of the notebooks and opened it.

"Have you seen those before, sirs?" Yale asked.

"No," I said, and Malcolm shook his head.

In Serena's looping handwriting, I read:

"Daddy and I had such fun in the garden this morning. He was teaching the dogs to fetch sticks and I was throwing the sticks. We picked a lot of beautiful daffodils and when we went indoors I put them all in vases in all the rooms. I cooked some lamb chops for lunch and made mint sauce and peas and roast potatoes and gravy and for pudding we had ice-cream and peaches. Daddy is going to buy me some white boots with zips and silver tassels. He calls me his princess, isn't that lovely? In the afternoon, we went down to the stream and picked some watercress for tea. Daddy took his socks off and rolled up his trousers and the boys no the boys weren't there I won't have them in my stories it was Daddy who picked the watercress and we washed it and ate it with brown bread. This evening I will sit on his lap and he will stroke my hair and call me his little princess, his little darling, and it will be lovely."

I flicked through the pages. The whole book was full. Speechlessly I handed it to Malcolm, open where I'd read.

"All the notebooks are like that," Yale said. "We've had them all read right through. She's been writing them for years, I would say."

"But you don't mean… they're recent?" I said.

"Some of them are, certainly. I've seen several sets of books like these in my career. Compulsive writing, I believe it's called. These of your sister's are wholesome and innocent by comparison. You can't imagine the pornography and brutality I've read. They make you despair."

Malcolm, plainly moved, flicking over pages, said, "She says I bought her a pretty red dress… a white sweater with blue flowers on it… a bright yellow leotard – I hardly know what a leotard is. Poor girl. Poor girl."

"She bought them herself," I said. "Three or four times a week."

Yale tilted the stack of notebooks up, brought out the bottom one and handed it to me. "This is the latest. It changes at the end. You may find it interesting."

I turned to the last entries in the book and with sorrow read: "Daddy is going away from me and I don't want him any more. I think perhaps I will kill him. It isn't so difficult. I've done it before." There was a space on the page after that, and then, lower down: "Ian is back with Daddy." Another space, and then,

"IAN IS AT QUANTUM WITH DADDY. I CANT BEAR IT."

After yet another space, she had written my name again in larger- still capitals "IAN" and surrounded it with a circle of little lines radiating outwards: an explosion with my name in the centre.

That was the end. The rest of the notebook was empty.

Malcolm read the page over my arm and sighed deeply. "Can I have them?" he said to Yale. "You don't need them, do you? There won't be a trial." Yale hesitated but said he saw no reason to retain them. He pushed the pile of books towards Malcolm and put the sweet tin on top. "And the lighthouse and clock," I said. "Could we have those?" He produced the Lego box from a cupboard, wrote a list of what we were taking on an official-looking receipt and got Malcolm to sign it.

"All very upsetting, Mr Pembroke," he said, again shaking hands, "but we can mark our case closed."

We took the sad trophies back to the Ritz, and that afternoon Malcolm wrote and posted cheques that would solve every financial problem in the Pembrokes' repertoire.

"What about the witches?" he said. "If Helen and that dreadful Edwin and Berenice and Ursula and Debs are all having their own share, what about those other three?"

"Up to you," I said. "They're your wives."

"Ex-wives." He shrugged and wrote cheques for them also. "Easy come, easy go," he said. "Bloody Alicia doesn't deserve it."

"Engines work better with a little oil," I said.

"Greasing their palms, you mean." He still didn't believe in it. Still felt he was corrupting them by giving them wealth. Still thinking that he could stay sane and reasonably sensible when he had millions, but nobody else could.

He wrote a final cheque and gave it to me. I felt awkward taking it, which he found interesting.

"You should have had double," he said.

I shook my head, reeling at noughts. "You've post-dated it," I said.

"Of course I have. I've post-dated all of them. I don't have that much in readies lying around in the bank. Have to sell a few shares. The family can have the promise now and the cash in a month."

He licked the envelopes. Not a cruel man, I thought.

On Tuesday, because I wished it, we went to see Robin.

"He won't remember Serena," Malcolm said.

"No, I don't expect so."

We went in the car I'd hired the day before for going to Quantum, and on the way stopped again to buy toys and chocolate and a packet of balloons. I had taken with us the Lego lighthouse and the Mickey Mouse clock, thinking they might interest Robin, over which Malcolm shook his head. "He won't be able to make them work, you know."

"He might remember them. You never know. They used to be his and Peter's, after all. Serena gave them the clock and made them the lighthouse."

Robin's room was very cold because of the open french windows. Malcolm tentatively went across and closed them, and Robin at once flung them open. Malcolm patted Robin's shoulder and moved away from the area, and Robin looked at him searchingly, in puzzlement, and at me the same way, as he sometimes did: trying, it seemed, to remember and never quite getting there.