“We certainly did,” Summer said, holding up a portable hard drive. “We obtained excellent footage of the uplift and should be able to identify some prime insertion points for the ground sensors.” She climbed past him, scurrying to locate the ship’s marine geologist so they could jointly review the seabed footage.

“I take it that means an immediate prep for another dive?” Dahlgren asked with a long face.

Dirk patted him on the shoulder. “I’m afraid it does, my friend.”

Dirk assisted Dahlgren in removing several heavy sets of battery packs that powered the submersible, swapping them with freshly charged replacements. While they worked on the aft deck, a large patrol boat appeared from shore. As the boat loosely circled the Alexandria, two casually dressed occupants on its open bridge studied the research ship with a look of displeasure. When the Alexandria moved off-site, the patrol boat ran back to shore.

“I wonder what those boys are up to,” Dahlgren said.

“They didn’t exactly look like government officials.” Dirk gazed toward the receding boat, and shoreline beyond. “I thought the coast around here was pretty well an empty desert.”

“A small freighter came cruising through while you were down. It appeared headed to shore, so there must be some sort of harbor nearby.”

They finished swapping batteries and completed an extensive predive safety check before tracking down Summer in one of the ship’s labs. She had assembled a crate of tiny battery-powered ground sensors that would track tremors and movements in the fault line. Each was contained in a stainless steel canister that sprouted a bright orange metal marker flag.

“We’ve surveyed in a perfect location,” Summer said. “What we want to do next is go back and bury ten sensors, five hundred meters apart, along the same track.” She looked to Dahlgren. “Can you drop us back at the same starting point?”

“Can a boll weevil find a Mississippi cotton field? You just go get yourself comfy in my submersible before I decide to put you over the side without it.” He stormed out of the lab, heading for the bridge to confer with the captain.

“What’s he so touchy about?” Summer asked.

“I made the mistake of telling him about the wreck we discovered,” Dirk said. “He’s mad that we found it in his submersible without him.”

She shook her head. “Boys and their toys.” Summer grabbed the sensors and carried them to a cage basket affixed to the front of the submersible. Once they were secured, she climbed inside and joined Dirk in reviewing the predive checklist.

Dahlgren appeared a few minutes later and ducked his head inside the hatch. “Good to go when y’all are.”

“We’re launch ready,” Dirk said. “Have a couple of cold ones waiting when we get back.”

“Sure, but they’re liable to be empty cold ones. Anything else?”