He lapsed into a kind of reverie, brooding about things, and it was a good thirty minutes later that he suddenly snapped out of it and checked on his position.

“Christ,” he said, “I must be twelve miles out.”

Which was close to the edge of things and that awesome place where everything simply dropped away and it was two thousand feet to the bottom, except for Thunder Point and that, he knew, was somewhere close. But no one ever dived there, the most dangerous reef in the entire region. Even Carney didn’t dive there. Strong currents, a nightmare world of fissures and channels. Carney had told him that years before an old diver had described it to him. A hundred and eighty feet on one side, then the ridge of the reef at around seventy, and two thousand feet on the other. The old boy had hit bad trouble, had only just made it to the surface, had never tried again. Few people even knew where it was anyway, and the sea out there was generally so turbulent that that in itself was enough to keep anyone away, but not today. It was a millpond. Baker had never seen anything like it. A sudden excitement surged in him and he switched on his fathometer, seeking the bottom, throttling back the engines, and then he saw it, the yellow ridged lines on the black screen.

He killed the engine and drifted, checking the depth reading until he was certain he was above the ridge of the reef at seventy feet, then scrambled round to the prow and dropped the anchor. After a while, he felt it bite satisfactorily and worked his way round to the deck. He felt incredibly cheerful as he stripped, pulled on the orange and blue nylon diving suit, then quickly assembled his gear, clamping a tank to his inflatable. He strapped the computer to the line of his air pressure gauge, then eased himself into the jacket, taking the weight of the tank, strapping the Velcro wrappers firmly across his waist and hooking a net diving bag to his weight belt as he always did with a spotlight inside in case he came across anything interesting. He pulled on a pair of diving gloves, then sat with his feet on the platform at the stern and pulled on his fins. He spat on his mask, rinsed it, adjusted it to his face, then simply stood up and stepped into the water.

It was incredibly clear and blue. He swam round to the anchor rope, paused, then started down, following the line. The sensation of floating in space was, as always, amazing, a silent, private world, sunlight at first, but fading as he descended.

The reef where the anchor was hooked was a forest of coral and sea grass, fish of every conceivable description, and suddenly a barracuda that was at least five feet long swerved across his vision and paused, turning toward him threateningly, which didn’t bother Baker in the slightest, because barracuda were seldom a threat to anyone.

He checked his dive computer. It not only indicated the depth he was at, but told him how long he was safe there and constantly altered its reading according to any change in depth he made during the dive. He was at this point at seventy feet and he turned and headed over to the left-hand side, where the reef slid down to a hundred and eighty. He went over the edge, then changed his mind and went up again. It was amazing how much an extra ten or fifteen feet reduced your bottom time.

There was a reasonably strong current; he could feel it pushing him to one side. He imagined what it must be like when conditions were bad, but he was damned if that was going to stop him having a look at the big drop. The edge of the reef over there was very clearly defined. He paused, holding on to a coral head and peered over, looking down the cliff face into a great blue vault that stretched into infinity. He went over, descended to eighty feet and started to work his way along.

It was interesting. He noted a considerable amount of coral damage, large sections having obviously been torn away, recently, presumably the result of the hurricane although they were on a fault line here and earth tremors were also common. Some distance ahead, there was a very obvious section where what looked like an entire overhang had gone revealing a wide ledge below, and there was something there, perched on the ledge yet part of it hanging over. Baker paused for a moment, then approached cautiously.

It was then that he received not only the greatest thrill of his diving career but the greatest shock of a long life. The object which was pressed on the ledge and partly sticking out over two thousand feet of water was a submarine.

During his naval service Baker had done a training course in a submarine when based in the Philippines. No big deal, just part of general training, but he remembered the lectures, the training films they’d had to watch, mainly Second World War stuff, and he recognized what he was looking at instantly. It was a type VII U-boat, by far the most common craft of its kind used by the German Kriegsmarine, the configuration was unmistakable. The conning tower was encrusted with marine growth, but when he approached he could still discern the number on the side – 180. The attack and control room periscopes were still intact and there was a snorkel. He recalled having heard that the Germans had gradually introduced that as the war progressed, a device that enabled the boat to proceed under water much faster because it was able to use the power of its diesel engines. Approximately two-thirds of it rested stern first on the ledge and the prow jutted out into space.

He glanced up aware of a school of horse-eyed jacks overhead mixed with silversides, then descended to the top of the conning tower and hung on to the bridge rail. Aft was the high gun platform with its 20mm cannon and forward and below him was the deck gun, encrusted, as was most of the surface, with sponge and coral of many colors.

The boat had become a habitat as with all wrecks, fish everywhere, yellow-tail snappers, angel and parrot fish and sergeant-majors and many others. He checked his computer. On the bridge he was at a depth of seventy-five feet and he had only twenty minutes at the most before the need to surface.

He drifted away a little distance to look the U-boat over. Obviously the overhang, which had recently been dislodged, had provided a kind of canopy for the wreck for years, protecting it from view, and at a site which was seldom visited, it had been enough. That U-boats had worked the area during the Second World War was common knowledge. He’d known one old sailor who’d always insisted that crews would come ashore on St. John by night in search of fresh fruit and water, although Baker had always found that one hard to swallow.

He swung over to the starboard side and saw what the trouble had been instantly, a large, ragged gash about fifteen feet long in the hull below the conning tower. The poor bastards must have gone down like a stone. He descended, holding on to a jagged, coral-encrusted edge, and peered into the control room. It was dark and gloomy in there, silverfish in clouds, and he got the spotlight from his dive bag and shone it inside. The periscope shafts were clearly visible, again encrusted like everything else, but the rest was a confusion of twisted metal, wires and pipes. He checked his computer, saw that he had fifteen minutes, hesitated, then went inside.

Both the aft and forward water-tight doors were closed, but that was standard practice when things got bad. He tried the unlocking wheel on the forward hatch, but it was immovable and hopelessly corroded. There were some oxygen bottles, even a belt of some kind of ammunition, and the most pathetic thing of all, a few human bones in the sediment of the floor. Amazing that there was any trace at all after so many years.

Suddenly he felt cold. It was as if he was an intruder who shouldn’t be here. He turned to go and his light picked out a handle in the corner, very like a suitcase handle. He reached for it, the sediment stirred and he found himself clutching a small briefcase in some kind of metal, encrusted like everything else. It was enough and he went out through the gash in the hull, drifted up over the edge of the reef and went for the anchor.