"Not unheard of," said one of the scientific team. "The Titanic broke in half as she sank."

"But she pitched downward at an extreme angle," Burch clarified. "I talked to the tugboat captain who had the Dolphin under tow when she sank. He claimed that she plunged under rapidly on a very shallow angle of not more than fifteen degrees. The Titanic dove at a forty-five-degree angle."

Giordino stared through the forward window at the sea ahead. "The most logical scenario is that she sank intact and shattered when she struck bottom. Her speed was probably somewhere between thirty and forty miles an hour."

Pitt shook his head. "If that were the case, the wreckage would be more concentrated. As we can see, she's spread all over the landscape."

"Then what caused her to break up on the way down?" Burch asked no one in particular.

"With luck," Pitt said slowly, "we'll find the answers when and if Sea Sleuth lives up to her name."

A dazzling orange sun rose across the flat blue horizon in the east as the Sea Sleuth hung under a new crane that had replaced the one dumped overboard during the rescue. It had been installed at the shipyard, and the crew had finished connecting the winch and its cable only hours earlier. Anticipation reigned as the oblong AUV was swung over the stern. The sea was fairly smooth, with waves running no more than three feet.

The ship's second officer directed the launch, and signaled to the crewman operating the winch when the vehicle was free of the stern. Then he waved an all-clear, and Sea Sleuth was lowered until just above the surface. One final check of her electronic systems, and then she was slowly dropped into the blue Pacific. As soon as she was afloat, a switch was activated, the electronic snap released and the lifting cable came free.

Inside the command center, Giordino sat in front of a console with a series of knobs and switches mounted around a joystick. He would pilot the Sea Sleuth during its journey into the abyss. As one of the team who'd written the probe's computer software, he was also the chief engineer in charge of its production. Few men knew more about the eccentricities of piloting an AUV four and half miles deep under the ocean than Giordino. As he glanced at the monitor that showed the AUV floating free of the ship in the water, he activated the valves of the buoyancy tank and watched as she descended beneath the waves and disappeared.