Skeleton Key

strength and concentration. The deeper he went, the colder it would get. He couldn‟t afford to hang around.
    He released the air from the BCD. At once the weights began to drag him down. The sea rose up and devoured him.
    He swam down, squeezing his nose and blowing hard—equalizing—to stop the pain in his ears.
    For the first time he was able to look around him. There was still enough sunlight to illuminate the sea and Alex caught his breath, marvelling at the astonishing beauty of the underwater world.
    The water was dark blue and perfectly clear. There were a few coral heads dotted around him, the shapes and colours as alien as anything it‟s possible to find on the earth. He felt completely at peace, the sound of his own breathing echoing in his ears and each breath releasing a cascade of silver bubbles. With his arms loosely folded across his chest, Alex let his fins propel him towards the shore. He was fifteen metres down, about five metres above the sea bed. A family of brightly coloured groupers swam past him; fat lips, bulging eyes and strange, misshapen bodies. Hideous and beautiful at the same time. It had been a year since Alex had last gone diving and he wished he had time to enjoy this. He kicked forward. The groupers darted away, alarmed.
    It didn‟t take him long to reach the edge of the cliff. The sea wall was of course much more than a wall; a seething mass of rock, coral, vegetation and fish life. A living thing. Huge gorgonian fans—leaves made of a thousand tiny bones—waved slowly from side to side. Clumps of coral exploded brilliantly all around him. A school of about a thousand tiny silver fish flickered past.
    There was a slither of movement as a moray eel disappeared behind a rock. He glanced at the dive computer. At least it seemed to be working. It told him he had been down for seven minutes.
    He had to find the entrance to the cave. That was why he was here. He forced himself to ignore the colours and sights of the underwater kingdom and concentrate on the rock face. The time he had spent taking his bearings before the dive paid off now. He knew more or less where the tower at the Casa de Oro stood in relation to the boat and swam in that direction, keeping the rock wall on his left. Something long and dark flashed past high above him. Alex saw it out of the comer of his eye but by the time he had turned his head it was gone. Was there a boat on the surface? Alex went down another couple of metres, searching for the cave.
    In the end, it wasn‟t hard to find. The entrance was circular, like a gaping mouth. This impression was heightened when Alex swam closer and looked inside. The cave hadn‟t always been underwater and over a period of time—millions of years—stalactites and stalagmites had grown, needle-sharp spears that hung down from the ceiling and protruded up from the floor. As always, Alex was unable to remember which was which. But even from a distance there was something menacing about the place. It was like looking into the open mouth of some giant, undersea monster. He could almost imagine the stalactites and stalagmites biting down, the whole thing swallowing him up.
    But he had to go in. The cave wasn‟t very deep and apart from the rock formations it was empty, with a wide, sandy floor. He was thankful for that. Swimming too far into an underwater cave, at sunset, on his own, really would have been madness. He could see the back wall from the entrance—and there were the first of the metal rungs! They were dark red now and covered in green slime and coral, but they were clearly man-made, disappearing up the far wall and presumably continuing all the way to the top of the Devil‟s Chimney. There was no sign of Turner or Troy. Had the two agents decided to climb up after all? Should Alex try to climb after them?
    Alex was about to swim forward when there was another movement just outside his field of vision. Whatever he had seen before had come back, swimming the other way. Puzzled, he looked up. And froze. He actually felt the air stop somewhere at the back of his throat. The last of the bubbles chased each other up to the surface. Alex just hung there, fighting for control. He wanted to scream. But underwater, it isn‟t possible to scream.
    He was looking at a great white shark, at least three metres long, circling slowly above him. The sight was so unreal, so utterly shocking, that at first Alex quite literally didn‟t believe his eyes.
    It had to be an