"When did you last see your father?" I amended.

"What on earth are you talking about?"

"That picture by Orchardson."

"Stop playing games. Where is Malcolm?"

"I don't know," I said.

"You're lying."

"Why do you want to find him?"

"WHY?" She was astonished. "Because he's out of his mind." She dug into her capacious handbag and brought out an envelope, which she thrust towards me. "Read that."

I opened the envelope and found a small piece of newspaper inside, a snipped paragraph without headline or provenance.

It said:

Second-string British contender is Blue Clancy, second in last year's Derby and winner this year of Royal Ascot's King Edward VII Stakes. Owner Ramsey Osborn yesterday hedged his Arc bets by selling a half-share in his four-year-old colt to arbitrageur Malcolm Pembroke, who launched into blood stock only this week with a two million guineas yearling at the Premium Sales. -

Ouch, I thought.

"Where did it come from?" I asked.

"What does it matter where it came from? That new 'Racing Patter' column in the Daily Towncrieras a matter of fact. I was drinking coffee this morning when I read it and nearly choked. The point is, is it true?"

"Yes," I said.

"What?"

"Yes," I said again. "Malcolm bought half of Blue Clancy. Why shouldn't he?"

"Sometimes," my mother said forcefully, "you are so stupid I could hit you." She paused for breath. "And what exactly is an arbitrageur?"

"A guy who makes money by buying low and selling high."

"Oh. Gold."

"And foreign currencies. And shares. And maybe racehorses."

She was unmollified. "You know perfectly well he's just throwing his money away to spite everybody."

"He didn't like Moira being killed. He didn't like being attacked himself. I shouldn't think he'll stop spending until he knows whether we have or haven't a murderer in the family, and even then…" I smiled, "he's getting a taste for it."

Joyce stared. "Moira was murdered by an intruder," she said.

I didn't answer.

She took a large swallow of her vodka and tonic and looked at me bleakly. She had been barely twenty when I was born, barely nineteen when Malcolm had whisked her headlong from an antique shop in Kensington and within a month installed her in his house with a new wedding ring and too little to do.

Malcolm, telling me now and again about those days, had said, "She understood figures, you see. And she could beat me at cards. And she looked so damned demure. So young. Not bossy at all, like she was later. Her people thought me an upstart, did you know? Their ancestors traced back to Charles II, mine traced back to a Victorian knife-grinder. But her people weren't rich, you know. More breeding than boodle. It was an impulse, marrying Joyce. There you are, I admit it. Turned out she didn't like sex much, more's the pity. Some women are like that. No hormones. So I went on seeing Alicia. Well, I would, wouldn't I? Joyce and I got on all right, pretty polite to each other and so on, until she found out about Alicia. Then we had fireworks, all hell let loose for months on end, do you remember? Don't suppose you remember, you were only four or five."

"Five and six, actually."

"Really? Joyce liked being mistress of the house, you know. She learned about power. Grew up, I suppose. She took up bridge seriously, and started voluntary work. She hated leaving all that, didn't much mind leaving me. She said Alicia had robbed her of her self-esteem and ruined her position in the local community. She's never forgiven her, has she?"

Joyce had returned to the small Surrey town where her parents had lived and later died, their social mantle falling neatly onto her able shoulders. She bullied the local people into good works, made continual bridge-tournament forays, earned herself a measure of celebrity, and no, had never forgiven Alicia.

In the bar at Sandown she was dressed, as always, with a type of businesslike luxury: mink jacket over grey tailored suit, neat white silk shirt, long strings of pearls, high-heeled shoes, green felt hat, polished calf handbag. "A well-dressed, well-bred, brassy blonde" Alicia had once called her, which was both accurate and unfair, as was Joyce's tart tit-for-tat opinion of Alicia as "White meat of chicken aboard the gravy train".

Joyce drank most of the rest of her vodka and said, "Do you really think one of the family is capable of murder?"

"I don't know."

"But who?"

"That's the question."

"it isn't possible," she insisted.

"Well," I said. "Take them one by one. Tell me why it's impossible in each individual case, according to each person's character. Start at the beginning, with Vivien."

"No, Ian," she protested.

"Yes," I said. "Help me. Help Malcolm. Help us all."

She gave me a long worried look, oblivious to the movement and noise going on all around us. The next race was already in progress but without noticeable thinning of the crowd who were watching it on closed circuit television above our heads. "Vivien," I prompted.

"Impossible, just impossible. She's practically dim-witted. If she was ever going to murder anybody, it would have been long ago and it would have been Alicia. Alicia ruined Vivien's marriage, just like mine. Vivien's a sniffler, full of self-pity. And why would she do it? For those three wimpish offspring?"

"Perhaps," I said. "They all need money. She hasn't enough herself to bail them out of their holes."

"It's still impossible."

"All right," I said. "How about Donald? And Helen?"

Donald had been ten, more than half Joyce's age, when she had married Malcolm, and he had been in and out of Quantum, as had Lucy and Thomas, whenever Malcolm had exercised his joint- custody rights and had them to stay. Joyce's lack of interest in children had definitely extended to her stepchildren, whom she'd found noisy, bad tempered and foul mannered, though Malcolm disagreed.

"Donald's a pompous, snobbish ass," she said now, "and as insecure as hell under the bluster. Malcolm thinks Helen's as brainless as she's pretty, but I'd say you don't need brains to murder, rather the opposite. I'd think Helen would fight like a fury to save her cubs from physical harm. But Moira wasn't threatening her cubs, not directly. I'd think Helen could be only a hot-blood killer, but so could most people, driven hard enough to defend themselves or their young."

I wondered if she knew about the school-fees crisis: if they hadn't directly told her, she had got them remarkably right. "Lucy?" I said.

"Lucy thinks everyone is inferior to herself, especially if they have more money."

Poor Lucy, I thought. "And Edwin?" I said.

Joyce frowned. "Edwin…"

"Edwin isn't impossible?" I asked.

"He never gets time off from running errands. Not enough time anyway for waiting around to catch Moira alone in her glass house."

"But in character?"

"I don't know enough about him, "Joyce confessed. "He yearns for money, that's for sure, and he's earned it, picking up after Lucy all these years. I don't know his impatience level."

"All right then," I said, "what about Thomas?" Thomas! "Joyce face looked almost sad. "He wasn't as insufferable as Donald and Lucy when he was little. I liked him best of the three. But that damned Vivien screwed him up properly, didn't she? God knows why he married Berenice. She'll badger him into the grave before he inherits, and then where will she be?" Joyce finished the vodka and said, "I don't like doing this, Ian, and I'm stopping right here."

Thomas, I thought. She wasn't sure about Thomas, and she doesn't want to say so. The analysis had all of a sudden come to an unwelcome, perhaps unexpected, abyss.

"Another drink?" I suggested.

"Yes. Gervase is drinking, did you know?"

"He always drinks."