They entered one of the labs and found it nearly pitch-black. With the lights off and the windows sealed, the only illumination was cast by a few tiny blue bulbs overhead. Pitt figured the lab’s air-conditioning unit must have been working nonstop as the temperature felt like the low fifties.

“Keep the door closed, please.”

As their eyes adjusted, they spotted the voice’s owner, a thin man in a jacket hunched over a large tank that almost filled the room. He wore a set of night vision goggles and was staring intently into the tank.

“Spying on the mating habits of the grunion again, Rudi?” Pitt asked.

Recognizing the voice, the man bolted upright and spun to greet the intruders.

“Dirk, I didn’t know it was you.” Gunn tore off the goggles and replaced them with a pair of horn-rimmed glasses. A brainy ex–Navy commander, Gunn served as NUMA’s Deputy Director. Like his boss, he escaped the confines of the Washington headquarters at every opportunity.

Pitt introduced Gunn to Ann.

“Why the cold, dark room?” she asked.

“Come take a look.” Gunn handed her the night vision goggles.

He guided her to the edge of the tank, where she slipped on the goggles and peered inside. A half dozen small fish swam in a lazy circle, glowing blue under the augmented light. But they were unlike any fish Ann had ever seen—flat translucent bodies, giant protruding eyes, and multiple rows of razor-sharp teeth jutting from their open mouths. She took a quick step back from the tank.

“What are those things? They’re hideous.”

“Rudi’s pet creatures of the deep,” Pitt said.

“Evermannella normalops is their scientific name,” Gunn said, “but we call them sabertooths. They’re an unusual species found only in very deep water. We discovered a large school of them thriving around a deepwater thermal vent near Monterey and decided to try and capture a few to study. Took quite a few dives with the submersible, but we brought up twenty of them. These are the last few we haven’t moved to shore yet.”

“They look like they’d eat you out of house and home.”

“Despite their appearance, we believe they are non-predatory. They’re actually quite docile. They don’t seem interested in eating other fish, so we think they may be scavengers.”

She shook her head. “I’m still not going to stick my hand in the tank.”

“Don’t worry,” Pitt said, “your cabin door has a lock on it, in case they grow legs in the night.”

“They’re no worse than a pet goldfish,” Gunn said. “Albeit, an ugly goldfish that can live a mile deep.”

“We’ll leave them in your care,” Pitt said. “Rudi, how soon can we shove off?”

Gunn tilted his head. “I think we can make like that pizza delivery outfit. Thirty minutes or less.”