Depressed, I drove home.

I put my head quietly round Scilla's door. Her room was dark, but I could hear her even breathing. She was still sound asleep.

Downstairs Joan and the children were sitting on the floor in front of the welcoming log fire playing poker. I had introduced them to the game one rainy day when the children were tired of snap and rummy and had been behaving very badly, quarrelling and shouting and raising tempers all round. Poker, the hitherto mysterious game of the cowboys in Westerns, had worked a miracle.

Henry developed in a few weeks into the sort of player you wouldn't sit down with twice without careful thought. His razor-sharp mathematical mind knew the odds to a fraction against any particular card turning up; his visual memory was formidable; and his air of slight bewilderment, calculated to be misleading, led many an unsuspecting adult straight into his traps. I admired Henry. He could out-bluff an angel.

Polly played well enough for me to be sure she would never lose continually in ordinary company, and even William knew a running flush from a full house.

They had been at it for some time. Henry's pile of poker chips was, as usual, three times as big as anyone else's.

Polly said, 'Henry won all the chips a little while ago, so we had to share them out and start all over again.'

Henry grinned. Cards were an open book to him and he couldn't help reading.

I took ten of Henry's chips and sat in with them. Joan dealt. She gave me a pair of fives and I drew another one. Henry discarded and drew two cards only, and looked satisfied.

The others threw in during the first two rounds. Then I boldly advanced two more chips to join the two on the table. 'Raise you two, Henry,' I said.

Henry glanced at me to make sure I was looking at him, then made a great show of indecision, drumming his fingers on the table and sighing. Knowing his habit of bluffing, I suspected he had a whipper of a hand and was scheming how to get me to disgorge the largest possible number of chips.

'Raise you one,' he said at last.

I was just about to put another two chips firmly out, but I stopped and said, 'Oh no you don't, Henry. Not this time,' and I threw in my hand. I pushed the four chips across to him. 'This time you get four and no more.'

'What did you have, Alan?' Polly turned my cards over, showing the three fives.

Henry grinned. He made no attempt to stop Polly looking at his cards too. He had a pair of Kings. Just one pair.

'Got you that time, Alan,' he said happily.

William and Polly groaned heavily.

We played until I had won back my reputation and a respectable number of Henry's chips. Then it was the children's bedtime, and I went up to see Scilla.

She was awake, lying in the dark.

'Come in, Alan.'

I went over and switched on the bedside light. The first shock was over. She looked calm, peaceful.

'Hungry?' I asked. She had not eaten since lunch the day before.

'Do you know, Alan, I am,' she said as if surprised.

I went downstairs and with Joan rustled up some supper. I carried the tray up and ate with Scilla. Sitting propped up with pillows, alone in the big bed, she began to tell me about how she had met Bill, the things they had done together, the fun they had had. Her eyes shone with remembered happiness. She talked for a long time, all about Bill, and I did not stop her until her lips began to tremble. Then I told her about Henry and his pair of Kings, and she smiled and grew calm again.

I wanted very much to ask her whether Bill had been in any trouble or had been threatened in any way during the last few weeks, but it wasn't the right time to do it. So I got her to take another of the sedatives the hospital had given me for her, turned off her light, and said good night.

As I undressed in my own room the tiredness hit me. I had been awake for over forty hours, few of which could be called restful. I flopped into bed. It was one of those times when the act of falling asleep is a conscious, delicious luxury.

Half an hour later Joan shook me awake again. She was in her dressing-gown.

'Alan, wake up for goodness' sake. I've been knocking on your door for ages.'

'What's the matter?'

'You're wanted on the telephone. Personal call,' she said.

'Oh no,' I groaned. It felt like the middle of the night. I looked at my watch. Eleven o'clock.

I staggered downstairs, eyes bleary with sleep.

'Hello?'

'Mr Alan York?'

'Yes.'

'Hold on, please.' Some clicks on the line. I yawned.

'Mr York? I have a message for you from Inspector Lodge, Maidenhead police. He would like you to come here to the police station tomorrow afternoon, at four o'clock.'

'I'll be there,' I said. I rang off, went back to bed, and slept and slept.

Lodge was waiting for me. He rose, shook hands, pointed to a chair. I sat down. The desk was clear now of everything except a neat, quarto-sized folder placed squarely in front of him. Slightly behind me, at a small table in the corner, sat a constable in uniform, pencil in hand, shorthand notebook at the ready.

'I have some statements here,' Lodge tapped the file, 'which I will tell you about. Then I have some questions to ask.' He opened the file and took out two sheets of paper clipped together.

'This is a statement from Mr J. L. Dace, Clerk of the Course of Maidenhead racecourse. In it he says nine of the attendants, the men who stand by to make temporary repairs to the fences during the races, are regularly employed in that capacity. Three of them were new this meeting.'

Lodge laid down this statement, and took out the next.

'This is a statement from George Watkins, one of the regular attendants. He says they draw lots among themselves to decide which fence each of them shall stand by. There are two at some fences. On Friday they drew lots as usual, but on Saturday one of the new men volunteered to go down to the farthest fence. None of them likes having to go right down there, Watkins says, because it is too far to walk back between races to have a bit on a horse. So they were glad enough to let the stranger take that fence, and they drew lots for the rest.'

'What did this attendant look like?' I said.

'You saw him yourself,' said Lodge.

'No, not really,' I said. 'All he was to me was a man. I didn't look at him. There's at least one attendant at every fence. I wouldn't know any of them again.'

'Watkins says he thinks he'd know the man again, but he can't describe him. Ordinary, he says. Not tall, not short. Middle-aged, he thinks. Wore a cap, old grey suit, loose mackintosh.'

'They all do,' I said gloomily.

Lodge said, 'He gave his name as Thomas Cook. Said he was out of work, had a job to go to next week and was filling in time. Very plausible, nothing odd about him at all, Watkins says. He spoke like a Londoner though, not with a Berkshire accent.'

Lodge laid the paper down, and took out another.

'This is a statement from John Russell of the St John Ambulance Brigade. He says he was standing beside the first fence in the straight watching the horses go round the bottom of the course. Because of the mist he says he could see only three fences: the one he was standing beside, the next fence up the straight, and the farthest fence, where Major Davidson fell. The fence before that, which was opposite him on the far side of the course, was an indistinct blur.

'He saw Major Davidson race out of the mist after he had jumped that fence. Then he saw him fall at the next. Major Davidson did not reappear, though his horse got up and galloped off riderless. Russell began to walk towards the fence where he had seen Major Davidson fall; then when you, Mr York, passed him looking over your shoulder, he began to run. He found Major Davidson lying on the ground.'