“It’s already transmitting,” the man growled, still nodding. The diver jumped down onto the deck and reached up to unfasten that dark, complicated helmet. “Do not remove that! You know the protocol. Do not remove your hood under any circumstances until we’re back on land!”

“There’s nothing here,” a woman’s voice objected. Feedback whined from the helmet. “I was underwater for ten minutes, and I didn’t see anything worth worrying about. I’m sweating like a dog in this thing.”

“Take it off, and I guarantee I’ll write you up.” The man’s voice was curt, and his companion hunched her shoulders resentfully but didn’t answer. They were already moving into the cabin, and Luce could just make out a few more voices coming from inside. A quiet motor had started, and Luce could see the chain running down to the anchor slowly spooling up. A few minutes later the boat was creeping out of the cove, its engines velvet-soft. The wake was so low and smooth that it didn’t even foam.

Luce squeezed her hands against the rock to calm the trembling, and her tail began to thrash. Something was very wrong.

It’s already transmitting, the man had said. Had the woman diver attached something to the rock? The worst possibility was that they’d installed some kind of underwater camera. Given the way the man had stared down at the screen in his hands, that even seemed likely. But if a camera was already transmitting images, Luce couldn’t very well disable it without revealing herself. She had a sudden, disquieting memory of the first time Catarina had warned her of what would happen if the humans ever learned mermaids existed. They’d poison the whole sea if they had to, Catarina had told her, just to kill all of us . . . Humans had every reason to want the mermaids dead. Leaving an underwater camera where it might capture images of mermaids—well, that was unthinkable. It simply couldn’t be allowed.

Did the intrusion of that quiet black boat mean the humans already suspected there were mermaids darting through their coastal waters, mermaids hunting their ships? It did seem peculiar that a diver was intruding on their territory not long after other ships had almost completely stopped navigating anywhere near them. Luce tried to shake the thought away. They were just scientists, she told herself, biologists or oceanographers, and the fact that they’d chosen to monitor this particular cove was purely coincidental.