Cullen thought this over. ‘Yes,’ he said drearily, ‘I suppose that makes sense. I suppose it must be Bill. I suppose I knew all the time that something—something awful had happened. He would never have left me without word. He would have written or telephoned or something to say why he hadn’t turned up on time. But what was he doing on a train to Scotland? What was he doing on a train anyhow?’

‘How: anyhow?’

‘If Bill wanted to go somewhere he would fly. He wouldn’t take a train.’

‘Lots of people take a night train because it saves time. You sleep and travel at the same time. The question is: why as Charles Martin?’

‘I think it’s a case for Scotland Yard.’

‘I don’t think the Yard would thank us.’

‘I’m not asking for their thanks,’ Cullen said tartly, ‘I’m instructing them to find out what happened to my buddy.’

‘I still don’t think they would be interested.’

‘They’d better be!’

‘You have no evidence at all that Bill Kenrick didn’t duck of his own accord; that he isn’t having a good time on his own until it is time to go back to OCAL.’

‘But he was found dead in a railway compartment!’ Cullen said in a voice that was nearly a howl.

‘Oh, no. That was Charles Martin. About whom there is no mystery whatever.’

‘But you can identify Martin as Kenrick!’

‘I can say, of course, that in my opinion that face in the snapshot is the face I saw in Compartment B Seven on the morning of March the 4th. Scotland Yard will say that I am entitled to my opinion, but that I am without doubt misled by a resemblance, since the man in Compartment B Seven is one Charles Martin, a mechanic, and a native of Marseilles, in the suburbs of which his parents still live.’

‘You’re very smooth in the part of Scotland Yard, aren’t you! All the same—’

‘I ought to be. I’ve worked there for more years than I care to think about. I shall be going back there a week Monday, as soon as my holiday is over.’

‘You mean that you are Scotland Yard?’

‘Not the whole of it. One of its minor props. Props in the support sense. I don’t carry cards in my fishing clothes but if you come up to my host’s house with me he will vouch for my genuineness.’

‘Oh. No. No, of course I believe you, Mr—er—’

‘Inspector. But we’ll stick to Mr, since I’m off duty.’

‘I’m sorry if I was fresh. It just didn’t occur to me—You see, you don’t expect to meet Scotland Yard in real life. It’s just something you read about. You don’t expect them to—to—’

‘To go fishing.’

‘No, I guess you don’t, at that. Only in books.’

‘Well, now that you have accepted me as genuine, and you know that my version of Scotland Yard’s reaction is not only accurate but straight from the horse’s mouth, what are we going to do?’

When Laura heard next morning that Grant intended to go in to Scoone instead of spending the day on the river, she was indignant.

‘But I’ve just made up a wonderful luncheon for you and Zoë,’ she said. He was left with the impression that her dismay was rooted in some cause more valid than a miscalculated meal, but his mind was too busy with more important matters to analyse trivialities.

‘There’s a young American staying at Moymore who has come to ask my help about something. I thought that he might take my place on the river, if no one has any objection. He has fished quite a bit, he tells me. Perhaps Pat would like to show him the ropes.’

Pat had come to breakfast in a state so radiant that the glow of it could be felt clear across the table. It was the first day of the Easter holidays. He looked with interest when he heard his cousin’s suggestion. There were few things in life that he enjoyed so much as showing someone something.

‘What’s his name?’ he asked.

‘Tad Cullen.’

‘What’s “Tad”?’

‘I don’t know. Short for Theodore, perhaps.’

‘M—m—m,’ said Pat doubtfully.

‘He’s a flyer.’

‘Oh,’ said Pat, his brow clearing. ‘I thought maybe with a name like that he was a professor.’

‘No. He flies to and fro across Arabia.’

‘Arabia!’ said Pat, rolling the R so that the mundane Scots breakfast table scintillated with reflections of the jewelled East. Between modern transport and ancient Bagdad, Tad Cullen seemed to have satisfactory credentials. Pat would ‘show him’ with pleasure.

‘Of course Zoë gets first choice of places to fish,’ Pat said.

If Grant had imagined that Pat’s infatuation would take the form of blushing silences and a mooning adoration, he was wrong. Pat’s only sign of surrender was the constant interjection of ‘me and Zoë’ into his conversation; and it was to be observed that the personal pronoun still came first.

So Grant borrowed the car after breakfast and went down to Moymore to tell Tad Cullen that a small boy with red hair and a green kilt would be waiting for him, with all appliances and means to boot, by the swing bridge across the Turlie. He himself would be back from Scoone in time to join them on the river some time in the afternoon, he hoped.

‘I’d like to come with you, Mr Grant,’ Cullen said. ‘Have you got a line on this thing? Is that why you’re going in to Scoone this morning?’

‘No. It’s to look for a line that I’m going in. There’s not a thing you can do just now, so you might as well have a day on the river.’

‘All right, Mr Grant. You’re the boss. What’s your young friend’s name?’

‘Pat Rankin,’ Grant said, and drove away to Scoone.

He had spent most of last night lying awake with his eyes on the ceiling, letting the patterns in his mind slip and fade into each other like trick camera work in a film. Constantly the patterns materialised, and broke, and dissolved, never the same for two moments together. He lay supine and let them dance their endless slow interlacing; taking no part in their gyrations; as detached as if they were a display of Northern Lights.

It was that way his mind worked best. It would also work the other way, of course. Work very well. In problems involving a time-place sequence for instance. In matters where A was at a spot X at 5.30 p.m. on the umpteenth inst, Grant’s mind worked with the tidiness of a calculating machine. But in an affair where motive was all, he sat back and let his mind loose on the problem. Presently, if he left it alone, it would throw up the pattern that he needed.

He still had no idea why Bill Kenrick had journeyed to the north of Scotland when he should have been travelling to Paris to meet his friend; still less had he any idea why he should have been travelling with another man’s papers. But he was beginning to have an idea as to why Bill Kenrick developed his sudden interest in Arabia. Cullen, looking at the world from his limited, flyer’s point of view, had thought of that interest in terms of flying routes. But Grant was sure that the interest had other origins. On Cullen’s own showing, Kenrick had exhibited none of the usual signs of ‘nerves’. It was unlikely that his obsession with the route he flew had anything to do with weather in any of its forms. Somewhere, sometime, on one of those flights over that ‘damned dreary’ route, Kenrick had found something that interested him. And that interest had begun on an occasion when he had been blown far off his course by one of the dust-storms that haunted the interior of Arabia. He had come back from that experience ‘concussed’. ‘Not listening to what was said to him.’ ‘Still back there.’

So this morning Grant was going in to Scoone to find out what might possibly have interested Bill Kenrick in the interior of that bleak and stony immensity; in the desert and forbidding half-continent that was Arabia. And for that, of course, he was going to Mr Tallisker. Whether it was the rateable value of a cottage or the composition of lava that one wanted to be enlightened about, one went to Mr Tallisker.