“What I don’t quite see,” said Lady Mary, “is why Pym’s is brought into it at all. Somebody at Pym’s is one thing, but if you say that the show is ‘run from Pym’s,’ it suggests something quite different-to me, anyhow. It sounds to me as though they were using Pym’s organization for something-doesn’t it to you?”

“Well, it does,” agreed her husband. “But how? And why? What has advertising got to do with it? Crime doesn’t want to advertise, far from it.”

“I don’t know,” said Wimsey, suddenly and softly. “I don’t know.” His nose twitched, rabbit-fashion. “Pymmy was saying only this morning that to reach the largest number of people all over the country in the shortest possible time, there was nothing like a press campaign. Wait a second, Polly-I’m not sure that you haven’t said something useful and important.”

“Everything I say is useful and important. Think it over while I go and tell Mrs. Gunner how to cook turbot.”

“And the funny thing is,” said Parker, “she seems to like telling Mrs. Gunner how to cook turbot. We could perfectly well afford more servants-”

“My dear old boy,” said Wimsey. “Servants are the devil. I don’t count my man Bunter, because he’s exceptional, but it’s a treat to Polly to kick the whole boiling out of the house at night. Don’t you worry. When she wants servants, she’ll ask for them.”

“I admit,” said Parker, “I was glad myself when the kids were old enough to dispense with a resident nurse. But look here, Peter, it seems to me you’ll be wanting a resident nurse yourself, if you want to avoid nasty accidents.”

“That’s just it. Here I am. Why? What are they keeping me for? Something unusually nasty?”

Parker moved quietly across to the window and peered out from a little gap in the short net blind.

“He’s there, I think. A repellent-looking young man in a check cap, playing with a Yo-Yo on the opposite pavement. Playing darned well, too, with a circle of admiring kids round him. What a grand excuse for loitering. There he goes. Three-leaf clover, over the falls, non-stop lift, round the world. Quite masterly. I must tell Mary to have a look at him and take a lesson. You’d better sleep here tonight, old man.”

“Thanks. I think I will.”

“And stop away from the office tomorrow.”

“I should, in any case. I’ve got to play in a cricket match at Brotherhood’s. Their place is down at Romford.”

“Cricket-match be damned. I don’t know, though. It’s nice and public. Provided the fast bowler doesn’t knock you out with a swift ball, it may be as safe as anywhere else. How are you going?”

“Office charabanc.”

“Good. I’ll see you round to the starting-point.”

Wimsey nodded. Nothing further was said about dope or danger until supper was over and Parker had departed for the Yelverton Arms. Then Wimsey gathered up a calendar, the telephone directory, a copy of the official report on the volume retrieved from Mountjoy’s flat, a scribbling-block and a pencil, and curled himself up on the couch with a pipe.

“You don’t mind, do you, Polly? I want to brood.”

Lady Mary dropped a kiss on the top of his head.

“Brood on, old thing. I won’t disturb you. I’m going up to the nursery. And if the telephone rings, take care it isn’t the mysterious summons to the lonely warehouse by the river, or the bogus call to Scotland Yard.”

“All right. And if the door-bell rings, beware of the disguised gas-inspector and the plain-clothes cop without a warrant-card. I need scarcely warn you against the golden-haired girl in distress, the slit-eyed Chink or the distinguished grey-haired man wearing the ribbon of some foreign order.”

He brooded.

He took from his pocket-book the paper he had removed, weeks earlier, from Victor Dean’s desk, and compared the dates with the calendar. They were all Tuesdays. After a little further cogitation, he added the date of the previous Tuesday week, the day when Miss Vavasour had called at the office and Tallboy had borrowed his pen to address a letter to Old Broad Street. To this date he appended the initial-“T”. Then, his mind working slowly backwards, he remembered that he had come to Pym’s on a Tuesday, and that Tallboy had come into the typists’ room for a stamp. Miss Rossiter had read out the name of his addressee-what had the initial been? “K”, of course. He wrote this down also, Then with rather more hesitation, he looked up the date of the Tuesday preceding Mr. Puncheon’s historic adventure at the White Swan, and wrote “W?”

So far, so good. But from “K” to “T” there were nine letters-there had not been nine weeks. Nor should “W” have come between “K” and “T”. What was the rule governing the letter-sequence? He drew thoughtfully at his pipe and sank into a reverie that was almost a pipe-dream, till he was aroused by a very distinct sound of yells and conflict from the floor above. Presently the door opened and his sister appeared, rather flushed.

“I’m sorry, Peter. Did you hear the row? Your young namesake was being naughty. He heard Uncle Peter’s voice and refused to stay in bed. He wants to come down and see you.”

“Very flattering,” said Wimsey.

“But very exhausting,” said Mary. “I do hate disciplining people. Why shouldn’t he see his uncle? Why should uncle be busy with dull detective business when his nephew is so much more interesting?”

“Quite so,” said Wimsey. “I have often asked myself the same question. I gather that you hardened your heart.”

“I compromised. I said that if he was a good boy and went back to bed, Uncle Peter might come up to say good night to him.”

“And has he been a good boy?”

“Yes. In the end. That is to say, he is in bed. At least, he was when I came down.”

“Very well,” said Wimsey, putting down his paraphernalia. “Then I will be a good uncle.”

He mounted the stairs obediently and found Peterkin, aged three, technically in bed. That is to say, he was sitting bolt upright with the blankets cast off, roaring lustily.

“Hullo!” said Wimsey, shocked.

The roaring ceased.

“What is all this?” Wimsey traced the course of a fat, down-rolling drop with a reproachful finger. “Tears, idle tears? Great Scott!”

“Uncle Peter! I got a naeroplane.” Peterkin tugged violently at the sleeve of a suddenly unresponsive uncle. “Look at my naeroplane, Uncle! Naeroplane, naeroplane!”

“I beg your pardon, old chap,” said Wimsey, recollecting himself. “I wasn’t thinking. It’s a beautiful aeroplane. Does it fly?… Hi! you needn’t get up and show me now. I’ll take your word for it.”

“Mummie make it fly.”

It flew very competently, effecting a neat landing on the chest of drawers. Wimsey watched it with vague eyes.

“Uncle Peter!”

“Yes, son, it’s splendid. Listen, would you like a speedboat?”

“What’s peed-boat?”

“A boat that will run in the water-chuff, chuff-like that.”

“Will it float in my barf?”

“Yes, of course. It’ll sail right across the Round Pond.”

Peterkin considered.

“Could I have it in my barf wiv’ me?”

“Certainly, if Mummie says so.”

“I’d like a boat in my barf.”

“You shall have one, old man.”

“When, now?”

‘Tomorrow.”

“Weally tomowwow?”

“Yes, promise.”

“Say thank-you, Uncle Peter.”

“Fank-you, Uncle Peter. Will it be tomowwow soon?”

“Yes, if you lie down now and go to sleep.”

Peterkin, who was a practically-minded child, shut his eyes instantly, wriggled under the bed-clothes, and was promptly tucked in by a firm hand.

“Really, Peter, you shouldn’t bribe him to go to sleep. How about my discipline?”

“Discipline be blowed,” said Peter, at the door.

“Uncle!”

“Good night!”

“Is it tomowwow yet?”

“Not yet. Go to sleep. You can’t have tomorrow till you’ve been to sleep.”

“Why not?”

“It’s one of the rules.”

“Oh! I’m asleep now, Uncle Peter.”

“Good. Stick to it.” Wimsey pulled his sister out after him and shut the nursery door.