"I'm very flattered, Strangman, of course." Beatrice moved over to the painting, examining her double, then turned in a swirl of brocade and stood by the rail, staring out over the water. "But I'm not sure whether I want to be cast in that role, Strangman."

"But you are, Miss DahI, inescapably." Strangman gestured the steward over to Bodkin, who was sitting in a quiet reverie, then slapped Kerans on the shoulder. "Believe me, Doctor, you'll soon see-"

"Good. I'm getting a little impatient, Strangman."

"What, after thirty million years you can't wait five minutes? I'm obviously bringing you back to the present."

Throughout the meal Strangman supervised the succession of wines, taking advantage of his absences from the table to confer with the Admiral. With the final brandies before them, Strangman sat down apparently for the last time, winking broadly at Kerans. Two of the scows had moved over to the inlet by the far side of the lagoon and disappeared into its mouth, while the third took up its position in the centre, from where it released a small firework display.

The last sunlight still lay over the water, but had faded sufficiently for the bright catherine wheels and rockets to flicker and dazzle, their sharp explosions etched clearly against the tinted crepuscular sky. The smile on Strangman's face grew broader and broader, until he lay back on his chesterfield grinning soundlessly to himself, the red and green flashes illuminating his saturnine features.

Uncomfortably, Kerans leaned forward to ask him when their surprise would materialise, but Strangman anticipated him.

"Well, haven't you noticed?" He glanced around the table. "Beatrice? Dr. Bodkin? You three are slow. Come out of deep time for a moment."

A curious silence hung over the ship, and involuntarily Kerans leaned against the rail to brace himself in case Strangman was about to set off an underwater explosive charge. Glancing down at the deck below, he suddenly saw the twenty or thirty members of the crew, looking motionlessly at the lagoon, their ebony faces and white singlets flickering with the ghostly light, like the crew of a spectral ship.

Puzzled, Kerans searched the sky and lagoon. The dusk had come in rather more quickly than he expected, the curtain walls of the buildings opposite sinking into shadow. At the same time the sky remained clear and visible in the sunset, the tops of the surrounding vegetation brilliantly tinted.

A low drumming sounded somewhere in the distance, the airpumps which had worked all day and whose noise had been masked by the pyrotechnic display. Around the ship the water had become strangely slack and lifeless, the low swells that usually disturbed it absent. Wondering whether an exhibition of underwater swimming had been arranged for a troupe of trained alligators, he peered down at the surface.

"Alan! Look, for heaven's sake! Beatrice, can you see?" Kerans kicked back his chair and leapt to the rail, pointing down in amazement at the water. "The level is going down!"

Looming just below the dark pellucid surface were the dim rectangular outlines of the submerged buildings, their open windows like empty eyes in enormous drowned skulls. Only a few feet from the surface, they drew closer, emerging from the depths like an immense intact Atlantis. First a dozen, then a score of buildings appeared to view, their cornices and fire escapes clearly visible through the thinning refracting glass of the water. Most of them were only four or five storeys high, part of a district of small shops and offices enclosed by the taller buildings that had formed the perimeter of the lagoon.

Fifty yards away the first of the roofs broke surface, a blunted rectangle smothered with weeds and algae, across which slithered a few desperate fish. Immediately half a dozen others appeared around it, already roughly delineating a narrow street. The upper line of windows emerged, water spilling from their ledges, fucus draped from the straggling wires that sagged across the roadways.

Already the lagoon had vanished. As they sank slowly downwards, settling into what seemed to be a large open square, they were now looking across a diffuse straggle of rooftops, punctuated by eroded chimneys and spires, the flat sheet of the surface transformed into a jungle of cubist blocks, at its boundaries merging into the higher ground of the enveloping vegetation. What remained of the water had formed into distinct channels, dark and sombre, eddying away around corners and into narrow alleyways.

"Robert! Stop it! It's horrible!" Kerans felt Beatrice seize his arm, her long blue nails biting through the fabric of his dinner jacket. She gazed out at the emerging city, an expression of revulsion on her tense face, physically repelled by the sharp acrid smells of the exposed water-weeds and algae, the damp barnacled forms of rusting litter. Veils of scum draped from the criss-crossing telegraph wires and tilting neon signs, and a thin coating of silt cloaked the faces of the buildings, turning the once limpid beauty of the underwater city into a drained and festering sewer.

For a moment Kerans fought to free his mind, grappling with this total inversion of his normal world, unable to accept the logic of the rebirth before him. First he wondered whether there had been a total climatic reversal that was shrinking the formerly expanding seas, draining the submerged cities. If so, he would have to make his way back to this new present, or be marooned millions of years away on the beach of some lost Triassic lagoon. But deep within his mind the great sun pounded dimly with a strength still undiminished, and beside him he heard Bodkin mutter: "Those pumps are powerful. The water is going down by a good two or three feet a minute. We're not far from the bottom now. The whole thing's fantastic!"

Laughter rocked out into the darkening air as Strangman rolled about mirthfully on the chesterfield, dabbing his eyes with a napkin. Released from the tension of staging the spectacle, he was now exulting in the three bewildered faces at the rail. On the bridge above him, the Admiral watched with dry amusement, the fading light glinting across his bare chest like a gong. Two or three men below were taking in the mooring lines, holding the orientation of the ship in the square.

The two scows which had moved over to the creek mouth during the firework display were floating behind a massive boom, and a foaming mass of water poured from the twin vents of a huge pumping system. Then the rooftops obscured their view across the interval, and the people on the deck were looking up at the blanched buildings of the square. Only fifteen or twenty feet of water remained, and a hundred yards away down one of the side streets they could see the third scow wending tentatively below the trailing Wires.

Strangman controlled himself and came over to the rail. "Perfect, don't you agree, Dr. Bodkin? What a jest, a really superb spectacle! Come on, Doctor, don't look so piqued, congratulate me! It wasn't too easy to arrange."

Bodkin nodded and moved away along the rail, his face still stunned. Kerans asked: "But how did you seal off the perimeter? There's no Continuous wall around the lagoon."

"There is now, Doctor. I thought you were the expert in marine biology. The fungi growing in the swamp mud outside consolidated the entire mass, for the last week there's only been one point of influx, took us five minutes to dam it up."

He gazed out brightly at the emerging streets in the dim light around them, the humped backs of cars and buses appearing through the surface. Giant anemones and star-fish flopped limply in the shallows, collapsing kelp straggled out of windows.

Numbly, Bodkin said: " Leicester Square."

His laughter vanishing, Strangman swung on him, his eyes peering rapaciously at the neon-covered porticos of the hulks of former cinemas and theatres.

"So you _do_ know your way around here, Doctor! A pity you couldn't have helped us before, when we were getting nowhere." He slammed the rail with an oath, jarring Kerans' elbow. "By Cod, though, we're really in business now!" With a snarl he flung himself away from them, kicking back the dining table, shouting up at the Admiral.

Beatrice watched him disappear below with alarm, a slender hand on her throat. "Robert, he's insane. What are we going to do-he'll drain all the lagoons."

Kerans nodded, thinking about the transformation of Strangman which he had witnessed. With the reappearance of the submerged streets and buildings his entire manner had changed abruptly. All traces of courtly refinement and laconic humour had vanished, he was now callous and vulpine, the renegade spirit of the hoodlum streets returning to his lost playground. It was almost as if the presence of the water had anaesthetised him, smothering his true character so that only the surface veneer of charm and moodiness remained.

Behind them the shadow of an office block fell across the deck, drawing a diagonal curtain of darkness over the huge painting. A few figures, Ester and the negro captain of gondoliers, still remained, and a single white face, a beardless member of the Council of Ten. As Strangman had prophesied, Beatrice had performed her symbolic role, and Neptune had deferred and withdrawn.

Kerans looked up at the round bulk of the testing station, poised on the cinema behind them like an enormous boulder on the edge of a cliff. Apparently eighty to ninety feet higher, the tall buildings around the lagoon perimeter now cut off half the sky, enclosing them in a dim canyon-floor world.

"It doesn't matter that much," Kerans temporised. He steadied her against his arm as the ship touched bottom and rolled slightly, crushing a small car under the port bow. 'When he's finished stripping the stores and museums they'll leave. Anyway, the rain-storms will be here in a week or two."

Beatrice cleared her throat distastefully, wincing as the first bats flickered among the rooftops, darting from one dripping eave to another. "But it's all so hideous. I can't believe that anyone ever lived here. It's like some imaginary city of hell. Robert, I need the lagoon."

"Well, we could leave and move south across the silt flats. What do you think, Alan?"

Bodkin shook his head slowly, still staring out blankly at the darkened buildings around the square. "You two go, I must stay here."

Kerans hesitated. "Alan," he warned him gently. "Strangman has everything he needs now. We're useless to him. Soon we'll simply be unwelcome guests."