Looking back at the wavering bikini-clad figure, he decided it would be foolish to cross the hundred-foot line by himself. He wanted her to come with him.

He flipped his powerful body upright. She was shaking her head, her lips moving as though he had done something to make her angry. A thought struck him. She had a wonderful figure, a nicely shaped mouth, but perhaps she was one of those ordinary women without gills? That didn’t have to be a problem. He had enough air on his back for them both. There was a recognized technique for sharing an aqualung. Like every experienced diver, Shayne had been checked out on it.

He took a deep breath, which made the light blink on and off, as though it was stage lighting with some kind of faulty connection. As he loosened his mouthpiece and offered it to her, she became more angry. He couldn’t be sure because of the face-plate, but she appeared to be frowning. She made an incomprehensible gesture. Propelling herself closer, she gripped the strap over his shoulder and began to tug.

A stab of irritation threatened to spoil Shayne’s pleasure. What was going on here? These face-plates had one disadvantage: they made communication difficult. If she didn’t want to go down to the reef with him, that was her business. He would go alone.

A quick flutter kick took him safely out of reach. She clutched her throat and pointed upward. There was a twinkle of light. She was gone.

He hung where he was, waving his arms slowly. He decided he liked the strange things that were happening to the light. There was something dull and monotonous about daylight and darkness. But this combined the qualities of both. In a moment he would continue down, to see if the effect was the same at a lower level. He was in no hurry. He would hang around here a little longer on the chance that the girl would change her mind and return.