Although he was working at home on the Friday afternoon, he was not in when Mrs Debs arrived from London. He says he had finished the job he'd been working on and decided to drive over to Henley and feed the ducks on the Thames. He found it peaceful. He liked the fresh air. He often did it, had done all his life, he said.

He didn't know Mrs Debs was finishing work as early as 3.30 that day, but he said that wouldn't have stopped him going out. They were independent people and not accountable to each other for every minute.

I stopped reading and lifted my head. It was true that Ferdinand had always been attracted to the ducks. I couldn't count the number of times we'd walked along the Henley towpath, scattering bread and listening to the rude laughter of the mallards. Malcolm was the one who took us, whenever Alicia started throwing plates. She squawked rather like the ducks, I'd thought, and had had enough sense not to say so.

I went on reading:

Mr Ferdinand is hard working and successful, going to be more so. (My opinion and his boss's.) He has planning, ability and energy. He is physically like his father, stocky and strong. (I remember Mr Pembroke 28 years ago. He threatened to throw me over his car when he found out I'd been following him, and I believed he could do it. Mr Ferdinand is the same.)

Mr F. can be very funny and good company, but his moods change to black disconcertingly fast. He is casual with his wife, not possessive. He is protective of his sister Serena. He is attentive to his mother, Mrs Alicia. He seem to have ambivalent feelings about Mr Pembroke and Mr Ian; I gathered from his inconsistent attitude that he liked them both in the past but no longer trusts them. Mr F. is capable of hate, I think. End of enquiry.

I put Debs and Ferdinand to the back of the pile but had no mental stamina left for the next section on Ursula and Gervase. I put all the notes into the envelope and ate some pub steak instead and decided I would see the family in the age-reversed order Norman West had handed me, taking the easy ones first. Where was the bravado that had led me to tell Malcolm at Cambridge that I would stay with him just because it was dangerous?

Where indeed.

Somewhere under the rubble of Quantum.

In the morning, I rode out on the windy Downs, grateful for the simplicity of horses and for the physical pleasure of using one's muscles in the way they were trained for. Vigour seemed to flow of its own accord in my arms and legs, and I thought that maybe it was the same for a pianist sitting down after a few days to play; there was no need to work out what to do with one's fingers, it was easy, it was embedded in one's brain, the music came without thought.

I thanked my host sincerely after breakfast and drove towards Quantum thinking of the telephone call I'd made to Malcolm the evening before. It had been nearly midnight for me: nearly six, early evening, for him.

He had arrived safely, he said, and Dave and Sally Cander were true blue cronies. Ramsey Osborn had flown down. The Canders were giving a party, starting in five minutes. He'd seen some good horses. He'd had some great new ideas for spending money (wicked chuckle). How were things in England?

He sounded satisfactorily carefree, having shed depression with the miles, and I said things were the same as when he left except that the house was wrapped up in tarpaulins. The state of the house troubled him for roughly ten seconds, and after that he said he and Ramsey might be leaving Lexington on Tuesday or Wednesday; he wasn't sure.

"Wherever you go," I said, "will you please give the Canders a telephone number where I can reach you?"

"I promise," he said blithely. "Hurry up with your passport, and come over."

"Soon."

"I've got used to you being with me. Keep looking round for you. Odd. Must be senile."

"Yes, you sound it."

He laughed. "It's a different world here, and I like it."

He said goodbye and disconnected, and I wondered how many horses he would have bought by the time I reached him.

Back at the pub in Cookham, I changed out of riding clothes and dutifully telephoned Superintendent Yale. He had nothing to tell me, nor I to tell him: the call was short.

"Where is your father?" he asked conversationally.

"Safe."

He grunted. "Phone me," he said, and I said, "Yes."

With a heavy lack of enthusiasm I returned to the car and pointed its nose towards Bracknell, parking in one of the large featureless car-parks and walking through to the High Street.

The High Street, long before, had been the main road through a minor country town; now it was a pedestrian backwater surrounded by the factories, offices and convoluted ring roads of mushroom progress. "Deanna's Dance and Aerobics Studio" looked like a wide shop-front flanked by a bright new shiny news agent on one side and on the other a photographic shop whose window display seemed to consist chiefly of postcard-sized yellow fluorescent labels with prices on, mostly announcing "20% OFF".

Deanna's studio consisted firstly of a reception area with a staircase on one side leading upwards. A young girl sitting behind the reception desk looked up and brightened when I pushed open the glass entrance door and stepped onto some thick grey carpet, but lost interest when I asked for Serena, explaining I was her brother.

"Back there," she said. "She's taking class at the moment."

Back there was through white-painted double doors. I went through and found myself in a windowless but brightly lit and attractive area of small tables and chairs, where several women sat drinking from polystyrene cups. The air vibrated with the pulse of music being played somewhere else, and when I again asked for Serena and was directed onwards, I came to its source.

The studio itself ran deeply back to end in a wall of windows overlooking a small strip of garden. The floor was of polished wood, sprung somehow so that it almost bounced underfoot. The walls were white except for the long left-hand one, which was entirely of looking-glass. The music, warm and insistent, invited rhythmic response.

Serena herself danced with her back to the mirror. Facing her, three spread-out rows, was a collection of clients, all female, bouncing in unison on springy ankles, arms and legs swinging in circles and kicks. On every face, concentration and sweat.

"Go for the bum," Serena commanded, looking happy, and her class with an increase of already frenetic energy, presumably went.

"Great, ladies, that's great," Serena said eventually, stopping jumping and switching off the music machine which stood in a corner near where I'd come in. She gave me an unfriendly glance but turned with radiance back to the customers. "If any of you want to continue, Sammy will be here within a minute. Take a rest, ladies."

A few of the bodies stayed. Most looked at the clock on the wall and filed panting into a door marked "changing rooms".

Serena said, "What do you want?"

"Talk."

She looked colourful but discouraging. She wore a bright pink long- sleeved body-stocking with white bouncing shoes, pink and white leg-warmers and a scarlet garment like a chopped off vest.

"I'll give you five minutes," she said.

She was hardly out of breath. A girl who was apparently Sammy Higgs came in in electric blue and started taking charge, and Serena with bad grace led me back through the refreshment area and the entrance hall and up the stairs.

"There are no classes up here just now. Say what you've come for and then go."

Upstairs, according to a notice on the wall, Deanna offered ballroom dancing tuition, also "ballet and posture". Serena stood with her hands on her skinny pink hips and waited.

"Malcolm wants me to find out who bombed Quantum," I said.

She glowered at me. "Well, I didn't."