“Thank you for allowing my men the use of your vessel, Captain,” Petrov said.

Madison scratched his head. “This is a first for me, but if your country and mine can cooperate in space, why not under the sea?” He turned to Austin. “Someone at NUMA's got a lot of pull. It's not anyone who can yank a U.S. Navy missile sub off its usual patrol for what seems to be, if you'll pardon the expression, a renegade special-ops mission.”

The four-hundred-twenty-five-foot Benjamin Franklin was one of four subs in its class that had been recruited because it was equipped for special operations. Even Sandecker's considerable influence wouldn't have superseded naval orders without approval, however masked, from the highest level.

Austin said, “This mission wouldn't have gotten off the ground if it weren't crucial.”

“Good luck, then,” the captain said. “We'll standby as long as we have to. Call us when you need a lift home.”

“You'll be the first to know.” Austin went over to a bank of computer screens.

“We're heading out, Hiram,” he said.

Yaeger sat in front of a keyboard where one of the sub's electronics people was explaining the vessel's computer setup. Sandecker had been reluctant to let Yaeger go on the mission, but Austin had pressed his case, saying that Hiram's computer expertise could be vital. The admiral relented after Austin had said he would bring Yaeger aboard only if the yacht's control center had been secured.

Yaeger shook hands with Austin and wished him good luck. “I'm still working to decipher the last piece of code,” he said. “I'll let you know if I break through the wall.”

At a signal from Austin, Petrov gave his men a series of commands. The boarding party made its way through the sub and crowded into the space under the loading hatch. A crewman climbed a ladder and opened the hatch cover, letting in a cold spray. Austin and Zavala went first, climbing through the hatch to emerge on the deck behind the sail. Petrov's men joined them and passed up two large plastic canisters. The canisters were opened, and compressed air hissed into the inflatable boats inside. The sub's crewman whispered, “Good luck,” and the hatch cover closed with a soft clunk.

Moonlight, filtered by the clouds, gave the sea a dark pewter cast. The tall sail, with its horizontal hydroplanes, looked like a giant robot from a science-fiction movie. Austin squinted through the gloom at the silhouetted yacht. Unlike its appearance in Boston Harbor, where it had been lit up like a Mississippi riverboat, the yacht was dark, except for a few lights on its radio masts and the yellow glow of cabin windows.