The work was painstaking, but their persistence paid off. Zavala snagged a metal cylinder bobbing in the water. It was about two feet long and six inches in diameter. Austin found a serial number and the name of its manufacturer etched into the metal.

Joe called his attention to movement at the top of the cliffs. Human specks could be seen lining the bluff. Austin didn't feel like answering questions for the local authorities. The fishermen were happy to head back to the ship. The deck was practically clear as they pulled up next to the Sea Robin. The ship was close to its normal pitch. Austin borrowed some money from Contos and tried to pay the fishermen for their services, but the brothers refused the cash. Juan explained through Zavala that showing them the hole in the fence was a service for which he would accept payment, but saving men from the sea was a moral duty. Austin thought about it, then persuaded the fishermen to accept a gift of friendship. After discussing it with Contos, they presented the happy fishermen with an outboard motor soon to be retired from service but in excellent shape.

The engines were started, and the ship slowly headed for open water. No leaks were detected. Contos set a course north. They left just in time. As they cruised along, a dark green helicopter appeared out of nowhere, circled the inlet several times, then dashed off to the north as quickly as it had come. They mingled with the boat traffic around Ensenada, where they spotted a Mexican coast guard boat steaming at full speed in the opposite direction. With the Sea Robin safely on its way, the NUMA men hit the showers and got into dry clothes. They rejoined Contos on the bridge. He had a fresh pot of coffee waiting.

“Okay, gentlemen,” he said, pouring two hot steaming mugs. “As skipper of this vessel, which you commandeered for what turned out to be a commando mission, I'd appreciate it if you would fill me in.”

Austin took a sip of the high-octane brew and decided he had never tasted anything more delicious.

“The explosion was a surprise to us,” he said. “Our basic mission was pretty simple. We wanted to check out the source of the heat that may have killed those whales. We think we found it.” He described the underwater structure as they first saw it, filling Contos in on the approach, the fake hazard buoys, the fishing net, and the high water temperature. Then he turned the narrative over to Joe.

Putting himself back underwater in the moments before the explosion, Zavala curled his hands as if he were clutching an in visible steering wheel.

“Everything's fine. We figure the high temperature readings are coming from the installation. You set off for a closer look, and I put the sub on the bottom to wait. The temps start to go off the charts, and I suggest you get back to the Brogan.”