Michael Shayne, wearing flippers and double-tank diving gear, sliced downward through the clear, green-gold water off Key Gaspar.

As always at this depth, he had a sense of perfect ease and freedom. He could do as he liked, go where he pleased. He was alone, with no duties and no obligations. The dangers down here, unlike those he kept meeting in the ordinary daylight world, were simple and predictable.

He said goodbye to the anchor rope, which led not only to the bottom but back to the surface. He went into a forward one-and-a-half somersault, for no other reason than to find out how it felt. He added a half twist at the end, grinning inside his mouthpiece. He was well aware that in the tight fraternity of scuba divers this kind of horseplay was frowned on except in pools. There was too good a chance of forgetting which way was down and which way was up. But today he had decided that the time had come to disregard the rules. They were meant, after all, for the cautious amateur, who wanted to move like a fish, in a fish’s element, while never forgetting for a moment that he was actually a man, with all the usual human worries.

He looked at the depth regulator on his wrist. He looked at it again, puzzled. The needle had given a sudden twitch. As a matter of fact, there appeared to be two needles, and the tiny numbers on the dial, which usually stayed in one spot to let the needle overtake them, were now whirling so rapidly that they kept overtaking each other. The mechanism was definitely out of order. Shayne was feeling too fishlike to let it bother him. Did a fish worry about where it was in relation to the surface? Obviously not.

He was enjoying himself more than he had in weeks. He had been shot at three times in the last twenty-four hours. Two of the men who had shot at him were dead; the third was in jail. This was just exactly the therapy he needed-clear water, absolute stillness except for the singing of the lung regulator, no criminals, no police, nothing living but himself and the fish.