“I think I’ll stay put for a moment,” she said. She did not at all fancy roaming in a Mithraic gloaming with the Major.

Alleyn said he, too, would find his own way back and the Van der Veghels, who had been photographing each other against the Sacrificial altar, decided to join him, not, Sophy thought, entirely to his delight.

Major Sweet left by one of the side doors. Alleyn disappeared behind the god, enthusiastically followed by the Van der Veghels. They could be heard ejaculating in some distant region. Their voices died and there was no more sound except, Sophy fancied, the cold babble of that subterranean stream.

“Come and sit down,” Grant said.

She joined him on one of the stone benches.

“Are you feeling a bit oppressed?”

“Sort of. “

“Shall I take you up? There’s no need to stay. That lot are all right under their own steam. Say the word.”

“How kind,” Sophy primly rejoined, “but, thank you, no. I’m not all that put out. It’s only—”

“Well?”

“I’ve got a theory about walls.”

“Walls?”

“Surfaces. Any surfaces.”

“Do explain yourself.”

“You’ll be profoundly unimpressed.”

“One never knows. Try me.”

“Mightn’t surfaces — wood, stone, cloth, anything you like — have a kind of physical sensitivity we don’t know about? Something like the coating on photographic film? So that they retain impressions of happenings that have been exposed to them. And mightn’t some people have an element in their physical make-up — their chemical or electronic arrangements or whatever — that is responsive to this and aware of it.”

“As if other people were colour-blind and only they saw red?”

“That’s the idea.”

“That would dispose rather neatly of ghosts, wouldn’t it?”

“It wouldn’t be only the visual images the surfaces retained. It’d be emotions too.”

“Do you find your idea an alarming one?”

“Disturbing, rather.”

“Well — yes.”

“I wonder if it might fit in with your Simon.”

“Ah,” ejaculated Grant, “don’t remind me of that, for God’s sake!”

“I’m sorry,” Sophy said, taken aback by his violence.

He got up, walked away and with his back turned to her said rapidly: “All right, why don’t you say it! If I object so strongly to all this show-off why the hell do I do it? That’s what you’re thinking, isn’t it? Come on. Isn’t it!”

“If I am it’s no business of mine. And anyway I did say it. Up above.” She caught her breath. “It seems ages ago,” said Sophy. “Ages.”

“We’ve dropped through some twenty centuries, after all. And I’m sorry to have been so bloody rude.”

“Think nothing of it,” Sophy said. She looked up at the sharply lit head of Mithras. “He is not very formidable after all. Plump and placid, really, wouldn’t you say? Isn’t it odd, though, how those blank eyes seem to stare? You’d swear they had pupils. Do you suppose—”

She cried out. The god had gone. Absolute darkness had closed down upon them like a velvet shutter.

“It’s all right,” Grant said. “Don’t worry. They do it as a warning for closing time. It’ll go on again in a second.”

“Thank the Lord for that. It’s — it’s so completely black. One might be blind.”

“ ‘All dark and comfortless’?”

“That’s from Lear, isn’t it? Not exactly a reassuring quotation if I may say so.”

“Where are you?”

“Here.”

In a distant region there was a rumour of voices: distorted, flung about some remote passage. Grant’s hand closed on Sophy’s arm. The god came into being again, staring placidly at nothing.

“There you are,” Grant said. “Come on. We’ll climb back into contemporary Rome, shall we?”

“Please.”

He moved his hand up her arm and they embarked on the return journey.

Through the insula, a left turn and then straight towards the iron stairway passing a cloisteral passage out of which came the perpetual voice of water. Up the iron stairway. Through the second basilica, past Mercury, and Apollo, and then up the last flight of stone steps towards the light, and here was the little shop: quite normal and bright.

The people in charge of the postcard and holy trinket stalls, a monk and two youths, were shutting them up. They looked sharply at Grant and Sophy.

“No more,” Grant said to them. “We are the last.”

They bowed.

“There’s no hurry,” he told Sophy. “The upper basilica stays open until sunset.”

“Where will the others be?”

“Probably in the atrium.”

But the little garden was quite deserted and the basilica almost so. The last belated sightseers were hurrying away through the main entrance.

“He’s mustered them outside,” Grant said. “Look — there they are. Come on.”

And there, in the outer porch where they had originally assembled, were Mr. Mailer’s guests in a dissatisfied huddle: the Van der Veghels, the Major, Lady Braceley, Kenneth and, removed from them, Alleyn. The two sumptuous cars were drawn up in the roadway.

Grant and Alleyn simultaneously demanded of each other: “Where’s Mailer?” and then, with scarcely a pause: “Haven’t you seen him?”

But nobody, it transpired, had seen Mr. Mailer.

“Not since he slouched off to find you,” Major Sweet shouted, glaring at Kenneth. “Down below, there.”

“Find me,” Kenneth said indifferently. “I don’t know what you’re talking about. I haven’t seen him.”

Alleyn said: “He went back to find you when you returned to photograph the Apollo.”

“He must have changed his mind then. Last I saw of him was — you know — it was — you know, it was just before I went back to Apollo.”

Kenneth’s voice dragged strangely. He gave an aimless little giggle, closed his eyes and reopened them sluggishly. By the light of day, Alleyn saw that the pupils had contracted. “Yes, that’s right,” Kenneth drawled, “I remember. It was then.”

“And he didn’t follow you and Lady Braceley, Major Sweet?”

“I imagined that to be perfectly obvious, sir. He did not.”

“And he didn’t join you, Lady Braceley, in the atrium?”

“If that’s the rather dismal little garden where the gallant Major dumped me,” she said, “the answer is no. Mr. Mailer didn’t join me there or anywhere else. I don’t know why,” she added, widening her terrible eyes at Alleyn, “but that sounds vaguely improper, don’t you think?”

Major Sweet, red in the face, said unconvincingly that he had understood Lady Braceley would prefer to be alone in the atrium.

“That,” she said, “would have rather depended on what was offering as an alternative.”

“I must say—” he began in a fluster but Alleyn interrupted him.

“Would you stay where you are, all of you,” Alleyn said. And to Grant: “You’re in charge, aren’t you? Be a good chap and see they stay put, will you?”

He was gone — back into the church.

“By God, that’s pretty cool, I must say,” fumed the Major. “Ordering people about, damn it, like some blasted policeman. Who the devil does he think he is!”

“I fancy,” Grant said, “we’d better do as he suggests.”

“Why!”

“Because,” Grant said with a half-smile at Sophy, “he seems to have what Kent recognized in Lear.”

“What the hell’s that?”

“Authority.”

“How right you are,” said Sophy.

“I think he’s gorgeous,” Lady Braceley agreed, “too compulsive and masterful.”

A long and uneasy silence followed this appraisal.

“But what’s he doing?” Kenneth suddenly asked. “Where’s he gone?”

“I’m blasted well going to find out,” the Major announced.

As he was about to carry out this threat, Alleyn was seen, returning quickly through the basilica.

Before Major Sweet could launch, as he clearly intended to do, a frontal attack, Alleyn said:

“Do forgive me, all of you. I’m afraid I was insufferably bossy but I thought it as well to go back and ask at the shop if Mr. Mailer had come through.”