He held the camera switch long enough to see that there was only smooth bottom ahead, then released it. Almost total blackness flooded in. For all practical purposes it was completely dark, no glimmer of light to mark their way.
For an instant Rick felt panic, but reason reasserted itself. It was instinctive to feel fear under such circumstances, he thought. Not only was he out of his own medium, air, but in a high-pressure realm inhabited by potentially dangerous creatures. He grinned inwardly at the thought. The most dangerous creatures in this vicinity were human.
A twinkle of light stopped him, but Zircon continued on and the connecting line tightened. Rick identified the twinkle as phosphorescence from some marine creature on the reef. There were many such in the ocean. He flashed the infrared light, saw that they were still heading properly, and cut it off again.
The rope at his belt tugged four times for danger! He stopped instantly, letting go of the camera with one hand while he reached for his belt knife. Then he saw what Zircon had seen, a glow in the water ahead and above them. Rick estimated quickly the distance they had traveled. There was no doubt of it. The frogmen were at the octopus cave!
He followed Zircon's lead, cutting the light off and on as necessary, as the big scientist moved ahead. The glow grew in intensity, but they were still too far away to see its exact position, or whether there were men around it.
Rick's heart beat faster, and his breathing speeded up appreciably. In spite of Zircon's plan to claim they were only checking on the frogmen's interest in the wreck, Rick knew that being discovered would mean serious trouble. He recalled Steve's warning that they were up against a ruthless enemy.
The question was, how close could they get without being seen? He could take pictures at ten feet, but at any greater distance the camera would be useless.
Zircon moved ahead, going slowly now. Rick followed, not bothering with the dark-light unit because the glow in the water was enough for a beacon. Then the glow faded for a moment as a figure crossed in front of it. Still Zircon moved ahead until Rick could see two additional, smaller glows that he identified as the belt lights the frogmen had been wearing.
Zircon continued on, still hugging the bottom, and Rick divined his intention. The big scientist was going to take them directly under the frogmen! It was logical, since the frogmen would not expect danger below.
Rick followed, staying just behind Zircon's flippers, feeling the wash of water from his wake. The light was nearly overhead now, and Rick saw dark figures moving. It was unreal, like a Hollywood motion picture, except that the tense music of a movie production was replaced only by the soft sighing of their regulators.