“Was it something to do with this G.P.F. business?” Manx said sharply, and after a pause. “You haven’t told anybody about this discovery, have you?”

She hadn’t told Alleyn. He had found out for himself. Miserably she shook her head. He stooped over her. “You mustn’t tell anybody, Lisle. That’s important. You realize how important, don’t you?”

Isolated sentences of an indescribable archness flashed up in her memory of that abominable page. “You don’t need to tell me that,” she said, looking away from his intent and frowning eyes, and suddenly burst out: “It’s such ghastly stuff, Ned. That magazine. It’s like one of our novelettes gone hay-wire. How you could!”

“My articles are all right,” he said, and. after a pause: “So that’s it, is it. You are a purist, aren’t you?”

She clasped her hands together and fixed her gaze on them. “I must tell you,” she said, “that if, in some hellish, muddled way, entirely beyond my comprehension, this G.P.F. business has anything to do with Rivera’s death…”

“Well?”

“I mean, if it’s going to — I mean — ”

“You mean that if Alleyn asks you point-blank about it, you’ll tell him?”

“Yes,” she said.

“I see.”

Carlisle’s head ached. She had been unable to face her breakfast and the drink he had given her had taken effect. Their confused antagonism, the sense of being trapped in this alien room, her personal misery: all these circumstances were joined in a haze of uncertainty. The whole scene had become unreal and unendurable. When he put his hands on her shoulders and said loudly: “There’s more to it than this. Come on. What is it?” she seemed to hear him from a great distance. His hands were bearing down hard. “I will know,” he was saying.

At the far end of the room a telephone bell began to ring. She watched him go to it and take the receiver off. His voice changed its quality and became the easy friendly voice she had known for so long.

“Hullo? Hullo, Fée darling. I’m terribly sorry, I should have rung up. They kept Lisle for hours grilling her at the Yard. Yes; I ran into her and she asked me to telephone and say she was so late she’d try for a meal somewhere at hand, so I asked her to have one with me. Please tell Cousin Cécile it’s entirely my fault and not hers. I promised to ring for her.” He looked at Carlisle over the telephone. “She’s perfectly all right,” he said. “I’m looking after her.”

If any painter, a surrealist for choice, attempted to set the figure of a working detective officer against an appropriate and composite background, he would turn his attention to rooms overlaid with films of dust, to objects suspended in unaccustomed dinginess, to ash-trays and table-cloths, unemptied waste bins, table littered with powder, dirty glasses, disordered chairs, stale food, and garments that retained an unfresh smell of disuse.

When Alleyn and Fox entered the Metronome at twelve-thirty on this Sunday morning, it smelt of Saturday night. The restaurant, serveries and kitchens had been cleaned but the vestibule and offices were untouched and upon them the aftermath of festivity lay like a thin pall of dust. Three men in shirt-sleeves greeted Alleyn with that tinge of gloomy satisfaction which marks an unsuccessful search.

“No luck?” Alleyn said.

“No luck yet, sir.”

“There’s the passage that runs through from the foyer and behind the offices to the back premises,” said Fox. “That’s the way the deceased must have gone to make his entrance from the far end of the restaurant.”

“We’ve been along there, Mr. Fox.”

“Plumbing?”

“Not yet, Mr. Alleyn.”

“I’d try that next.” Alleyn pointed through the two open doors of Caesar Bonn’s office into the inner room. “Begin there,” he said.

He went alone into the restaurant. The table he and Troy had sat at was the second on the right. The chairs were turned up on its surface. He replaced one of them and seated himself. “For twenty years,” he thought, “I have trained my memory and trained it rigorously. This is the first time I have been my own witness in a case of this sort. Am I any good or am I rotten?”

Sitting alone there, he re-created his scene, beginning with small things: the white cloth, the objects on the table, Troy’s long hand close to his own and just within his orbit of vision. He waited until these details were firm in his memory and then reached out a little further. At the next table, her back towards him, sat Félicité de Suze in a red dress. She turned a white carnation in her fingers and looked sidelong at the man beside her. He was between Alleyn and the lamp on their table. His profile was rimmed with light. His head was turned towards the band dais. On his right, more clearly visible, more brilliantly lit, was Carlisle Wayne. In order to watch the performance she had swung round with her back half-turned to the table. Her hair curved back from her temples. There was a look of compassion and bewilderment in her face. Beyond Carlisle, with her back to the wall, a heavy shape almost obscured by the others, sat Lady Pastern. As they moved he could see in turn her stony coiffure, her important shoulders, the rigid silhouette of her bust; but never her face.

Raised above them, close to them, a figure gestured wildly among the tympani. This was a vivid picture because it was contained by a pool of light. Lord Pastern’s baldish head darted and bobbed. Metallic high lights flashed among his instruments. The spot light shifted and there in the centre of the stage was Rivera, bent backwards, hugging his piano-accordion to his chest. Eyes, teeth, and steel and mother-of-pearl ornament glittered. The arm of the metronome pointed fixedly at his chest. Behind, half-shadowed, a plump hand jerked up and down, beating the air with its miniature baton. A wide smile glistened in a moon face. Now Lord Pastern faced Rivera on the perimeter of the light pool. His revolver pointed at the contorted figure, flashed, and Rivera fell. Then the further shots and comic falls and then… In the deserted restaurant Alleyn brought his hands down sharply on the table. It had been then, and not until then, that the lights began their infernal blinking. They popped in and out down the length of the metronome and about its frame, in and out, red green, blue, green red. Then, and not until then, had the arm swung away from the prostrate figure and, with the rest of that winking stuttering bedazzlement, gone into action.

Alleyn got up and mounted the bandstand. He stood on the spot where Rivera had fallen. The skeleton tower of the metronome framed him. The reverse side of this structure revealed its electrical equipment. He looked up at the pointer of the giant arm which was suspended directly above his head. It was a hollow steel or plastic casting studded with miniature lights and for a moment reminded him fantastically of the jewelled dart. To the right of the band-room door and hidden from the audience by the piano, a small switchboard was sunk in the wall. Happy Hart, they had told Alleyn, was in charge of the lights. From where he sat at the piano and from where he fell to the floor he could reach out to the switches. Alleyn did so, now, pulling down the one marked “Motor.” A hidden whirring sound prefaced the first loud clack. The giant downward-pointing arm swept semi-circularly across, back, across and back to its own ratchet-like accompaniment. He switched on the lights and stood for a moment, an incongruous figure, motionless at the core of his kaleidoscopic setting. The point of the arm, flashing its lights, swept within four inches of his head and away and back and away again. “If you watched the damn’ thing for long enough I believe it’d mesmerize you,” he thought and turned off the switches.

Back in the offices he found Mr. Fox in severe control of two plumbers who were removing their jackets in the lavatory.

“If we can’t find anything fishing with wires, Mr. Alleyn,” Fox said, “it’ll be a case of taking down the whole job.”