It was 11.45an d there was very little cloud, the sky brilliant with stars, and the moonlight danced across the waves, leaving a trail of silver behind it. The dinghy lifted high on a large swell and swung in towards the great finger of rock which marked the western tip of the island. Mallory opened the throttle again. For a moment the dinghy seemed to stand still and then it forged ahead.
They rounded the point, fighting the cross-currents, Guyon cursing steadily as water slopped over the sides, and then they were sweeping into calmer water. Beyond, St. Pierre and the Gothic towers of the castle were dark against the sky.
Mallory throttled down again and the dinghy coasted on, the sound of her motor a murmur on the wind. The great reef running between the two islands was deceptively inno-cent in the moonlight. Waves rolling in from the sea splashed lazily across the rocks, now and then a curtain of white spray lifting into the night like silver lace.
He took the dinghy into the calm waters of the Middle Passage until they reached the first point where the roof closed in and water boiled across great jagged black teeth. He cut the motor and the dinghy slowed and ground gently against a sloping, weed-covered shoulder of rock. Guyon hooked the painter into a crevasse and looked towards St. Pierre through the night-glasses.
“About a quarter of a mile. A long swim.”
“Not with the aquamobile,” Mallory said.
Guyon got it over the side, the dinghy heeling danger-ously. “Rather you than me. The water’s like ice. How long will you be?”
Mallory shrugged. “No more than half an hour. I’ve no intention of hanging around at the other end.”
He fitted the rubber mouthpiece between his teeth and adjusted his air supply, touched the knife briefly at his belt and clambered awkwardly over the side on to the reef. He waded into the water, swam to the other side of the dinghy and reached for the aquamobile. Guyon smiled once and Mallory nodded and sank beneath the surface.
Moonlight filtered down through the water, probing into the depths. When he passed beneath the surface of the reef and came into the Middle Passage he entered a darker, more sinister, world.
He switched on the powerful spot mounted on top of the scooter and the shaft of light pierced through the darkness in front of him, splaying against the rocks that arched above his head.
He tilted the nose of the aquamobile and- went down gently, leveling out at twenty feet. Although his top speed was no more than three knots, he seemed to rush at a ter-rifying speed into the wall of grey mist that was the edge of his visibility. The great, arched nave of the reef stretched into infinity before him, the water breaking against his mask.
And then he was through and moving into a strange, unreal landscape of jumbled rocks and pale forests of sea-weed waving languidly in the diffused moonlight. He sur-faced and looked up at the cliffs of St. Pierre, the pointed towers of the castle dark against the sky.
The moonlight splashed across the face of the cliffs, pick-ing out the dark mouth of the cave. It was now high water and there was no more than a ten- or twelve-foot clearance. Mallory turned the nose of the aquamobile down and leveled out at forty feet. He switched off the.spot and moved into a grey phosphorescent mist.
The great fault in the sea-bed dropped beneath him. At least ten fathoms, Anne had said, slicing into the heart of the island. The mist seemed to swing to one side like a curtain, revealing the entrance to the cave, a good sixty feet across as it widened on its way down.
He drifted in, grey-green walls moving past on either side. The water lightened, the grey merging into aquamarine as artificial light seeped down from the surface. He moved in close to the wall and went forward cautiously.
He stopped abruptly, switching off the aquamobile. From this point on the rough wall of the cave merged into the jetty, great square blocks of masonry like the foundations of some ancient fort descending into the depths. He started up cautiously and immediately the grey-black underbelly of the submarine appeared from the mist.