“As we supposed,” Alleyn agreed. “Mrs. Thomasina Twitchett’s work.”

“A nice fish; she’s been, say, two pound, but nothing to the Old ’Un,” said the sergeant.

Alleyn laid the paper and its contents on a step of the stile and hung fondly over it. Mrs. Twitchett, if indeed it was she, had made short work of most of the Colonel’s trout, if indeed this was his trout. The body was picked almost clean and some of the smaller bones had been chewed. The head appeared to have been ejected after a determined onslaught and the tail was semi-detached. But from the ribs there still depended some pieces of flesh and rags of skin that originally covered part of the flank and belly of the fish, and it was over an unlovely fragment of skin that Alleyn pored. He laid it out flat, using two pairs of pocket tweezers for the purpose, with a long finger pointed to something that might have been part of an indented scar. It was about a quarter of an inch wide and had a curved margin. It was pierced in one place as if by a short spike.

“Now blow me down flat,” Alleyn exulted, “if this isn’t the answer to the good little investigating officer’s prayer. See here, Fox, isn’t this a piece of the sort of scar we would expect to find? And look here.”

Very gingerly he turned the trout over and discovered, clinging to the other flank, a further rag of skin with the apex of a sharp triangular gap in it.

“Sink me if I don’t have a look,” Alleyn muttered.

Under Oliphant’s enchanted gaze, he opened his case, took from it a flat enamel dish, which he laid on the bottom step of the stile, and a small glass jar with a screw-on lid. Using his tweezers, he spread out the piece of skin with the triangular gap on the plate. From the glass jar he took the piece of skin that had been found on the sharp stone under the Old ’Un. Muttering and whistling under his breath, and with a delicate dexterity, he laid the second fragment beside the first, opened it out and pushed and fiddled the one into the other as if they were pieces of a jigsaw puzzle. They fitted exactly.

“And that,” Alleyn said, “is why Mrs. Twitchett met us last night smelling of fresh fish when she should have been stinking of liver. O, Fate! O, Nemesis! O, Something or Another!” he apostrophized. “Thy hand is here!” And in answer to Oliphant’s glassy stare he added, “You’ve done damned handily, Sergeant, to pick this up so quickly. Now, listen, and I’ll explain.”

The explanation was detailed and exhaustive. Alleyn ended it with an account of the passage he had read in Colonel Cartarette’s book. “We’ll send out a signal to some piscatorial pundit,” he said, “and get a check. But if the Colonel was right, and he seems to have been a conscientious, knowledgeable chap, our two trout cannot exhibit identical scales. The Colonel’s killer, and only his killer can have handled both fish. We do a round-up of garments, my hearties, and hope for returns.”

Sergeant Oliphant cleared his throat and with an air of modest achievement stooped behind a briar bush. “There’s one other matter, sir,” he said. “I found this at the bottom of the hill in a bit of underbrush.”

He straightened up. In his hand was an arrow. “It appears,” he said, “to have blood on it.”

“Does it, indeed?” Alleyn said and took it. “All right, Oliphant. Damn’ good show. We’re getting on very prettily. And if,” he summarized for the benefit of the gratified and anxious Oliphant, “if it all tallies up as I believe it must, then the pattern will indeed begin to emerge, won’t it, Fox?”

“I hope so, Mr. Alleyn,” Fox rejoined cheerfully.

“So off you go, Oliphant,” Alleyn said. “Drive Mr. Fox to the station, where he will ring the Yard and the Natural History Museum. Deliver your treasure-trove to Dr. Curtis. I hope to have the rest of the exhibits before this evening. Come on, chaps, this case begins to ripen.”

He led them back to the valley, saw Oliphant and Fox on their way with an accumulation of gear and objects of interest, and himself climbed up the hill to Nunspardon.

Here, to his surprise, he ran into a sort of party. Shaded from the noontide sun on the terrace before the great house were assembled the three Lacklanders, Kitty Cartarette and Rose. It was now half past twelve, and a cocktail tray gave an appearance of conviviality to a singularly wretched-looking assembly. Lady Lacklander seemed to have retired behind her formidable façade leaving in her wake an expression of bland inscrutability. George stood in a teapot attitude: one hand in his jacket pocket, the other on the back of a chair; one neatly knickered leg straight, one bent. Mark scowled devotedly upon Rose, who was pale, had obviously wept a great deal and seemed in addition to her grief to be desperately worried. Kitty, in a tweed suit, high heels and embroidered gloves, was talking to George. She looked exhausted and faintly sulky, as if tragedy had taken her by surprise and let her down. She lent an incongruous note to a conversation piece that seemed only to lack the attendant figures of grooms with hounds in leashes. Her voice was a high-pitched one. Before she noticed Alleyn, she had completed a sentence and he had heard it: “That’s right,” she had said, “Brierley and Bentwood,” and then she saw him and made an abrupt movement that drew all their eyes upon him.

He wondered how many more times he would have to approach these people through their gardens and from an uncomfortable distance. In a way, he was beginning to enjoy it. He felt certain that this time, if George Lacklander could have managed it, the waiting group would have been scattered by a vigorous gesture, George himself would have retired to some manly den and Alleyn, in the ripeness of time, would have been admitted by a footman.

As it was, all of them except Lady Lacklander made involuntary movements which were immediately checked. Kitty half rose as if to beat a retreat, looked disconsolately at George and sank back in her chair.

“They’ve been having a council of war,” thought Alleyn.

After a moment’s further hesitation Mark, with an air of coming to a decision, put his chin up, said loudly, “It’s Mr. Alleyn,” and came to meet him. As they approached each other, Alleyn saw Rose’s face, watchful and anxious, beyond Mark’s advancing figure, and his momentary relish for the scene evaporated.

“Good morning,” Alleyn said. “I’m sorry to reappear so soon and to make a further nuisance of myself. I won’t keep you long.”

“That’s all right,” Mark said pleasantly. “Who do you want to see?”

“Why, in point of fact, all of you, if I may. I’m lucky to find you in a group like this.”

Mark had fallen into step with him and together they approached the group.

“Well, Rory,” Lady Lacklander shouted as soon as he was within range, “you don’t give us much peace, do you? What do you want this time? The clothes off our backs?”

“Yes,” Alleyn said, “I’m afraid I do. More or less.”

“And what may that mean? More or less?”

“The clothes off your yesterday-evening backs, if you please.”

“Is this what my sporadic reading has led me to understand as ‘a matter of routine’?”

“In a way,” Alleyn said coolly, “yes. Yes, it is. Routine.”

“And who,” Kitty Cartarette asked in a careworn voice of nobody in particular, “said that a policeman’s lot is not a happy one?”

This remark was followed by a curious little gap. It was as if her audience had awarded Kitty a point for attempting, under the circumstances, her small joke but at the same time were unable to accept her air of uncertain intimacy, which apparently even George found embarrassing. He laughed uncomfortably. Lady Lacklander raised her eyebrows, and Mark scowled at his boots.

“Do you mean,” Lady Lacklander said, “the clothes that we were all wearing when Maurice Cartarette was murdered?”

“I do, yes.”

“Well,” she said, “you’re welcome to mine. What was I wearing yesterday, George?”