Stunned at what he witnessed below, seeing two men in the same uniform as the searchers' shooting at each other, the pilot hesitated before taking any action. By the time he set up to fire the machine gun mounted under the nose of the M-C Explorer, Giordino was pouring a startling volume of bullets into the unarmored helicopter. As if a sewing machine were stitching a hem, the constant stream of fire moved up the side of the fuselage and sprayed through the windshield into the cockpit. Then all went silent as the rifles' ammo magazines ran empty.

The Explorer seemed to hang suspended, then it abruptly lurched, fell out of control, crashed into the side of the mountain three hundred yards below the archway, and burst into flames. Giordino dropped his rifles and rushed to the side of Gunn, who was clutching his wounded leg.

"Stay where you are!" Giordino ordered. "Do not move."

"Merely a scratch," Gunn forced through clenched teeth.

"Scratch, hell, the bullet broke your tibia. You've got a compound fracture."

Gunn looked up at Giordino through the pain and managed a tight grin. "I can't say I think a hell of a lot about your bedside manner."

Giordino didn't pay any attention to Gunn's heroics. He pulled out a lace from his shoe and made a temporary tourniquet around the thigh above the knee.

"Can you hold that for a minute?"

"I guess I'd better if I don't want to bleed to death," Gunn groaned.

Giordino ran back into the tunnel, through the smoldering chamber, and from behind the cave-in retrieved his backpack, which contained a first-aid kit. He was back in a few minutes and worked swiftly, proficiently, disinfecting the wound and doing his best to stem the flow of blood.

"I'm not even going to think about setting it," said Giordino. "Better to let a doctor do it in Cape Town." He didn't want to move the little man, so he made him as comfortable as possible and covered him from the drizzle with a plastic sheet out of his backpack. His next chore was to call the admiral, report on Gunn's wound, and beg for a quick rescue.

When he finished his conversation with Sandecker, he put the phone in his pocket and stared at the burning helicopter on the mountain slope below.

"Insanity," he said softly to himself. "Pure, unadulterated insanity. What cause can possibly motivate so many men to kill and be killed?" He could only hope the answers would come sooner rather than later.

"One hundred and sixty feet to the bottom," said Ira Cox, staring into the sinister hole in the ice that marked the grave of the smashed and sunken U-boat. "Are you sure you want to do this?"

"Repairs to the Polar Storm's engine room and bridge by the Navy damage-control team won't be completed for another two hours," explained Pitt. "And since the ship carried Arctic diving equipment on board, I can't pass up the opportunity to investigate inside the sub's hull."

"What do you expect to find?" asked Evie Tan, who had accompanied Pitt and a small crew from the ship.

"Logbook, papers, reports, anything with writing on it that might lead to who was in command and what hidden location she sailed from."

"Nazi Germany in 1945," Cox said with a little smile, but not trying to be clever.

Pitt sat on the ice and pulled on his swim fins. "Okay, but where has she been hiding for the last fifty-six years?"

Cox shrugged and tested Pitt's underwater communication system. "Can you hear me okay?"

"You're blasting my eardrums. Turn down the volume."

"How's that?"

"Better," Pitt's voice came over a speaker set up in an operations tent beside the opening in the ice.

"You shouldn't be going alone," said Cox.

"Another diver would only get in my way. Besides, I have more than twenty dives under Arctic ice under my belt, so it's not a new experience."

In the warmth of a generator-heater in the tent, Pitt slipped on a Divex Armadillo Hot Water Suit, with internal and external tubing that circulated warm water throughout the entire body, including the hands, feet, and head. The heated water came from a combination heater and pump that forced it through an umbilical hose into the suit's inlet manifold that enabled Pitt to regulate the flow. He wore an AGA MK-II full face mask adapted to wireless communications. He elected to carry air tanks for ease of movement rather than rely on the surface support system. A quick check of his Substrobe Ikelite underwater dive light and he was ready to go.

"Good luck," shouted Evie, to make herself heard through Pitt's hood and face mask. She then busied herself shooting photos of Pitt as he sat on the edge of the ice before dropping off into the icy water. "You sure I can't talk you into taking photos with a watertight camera down there?"

Pitt gave a brief shake of his encased head as his voice came over the speaker. "I won't have time to play photographer."

He gave a wave and rolled into the water, pushing off from the ice with his finned feet. He dove and leveled out at ten feet while he vented the air from his dry suit and waited to see if its heating element was compensating for the frigid drop in temperature. A cautious diver, in all his years of diving, Pitt had rarely encountered problems underwater. He constantly talked to himself, sharpening his mind to question and probe his surroundings, and monitoring his instrument gauges and body condition.

Beneath the ice pack, which was a little over three feet thick, he found a wildly different world. Staring upward, Pitt imagined the underside of the ice as looking like the surface of an unknown planet deep in the galaxy. Transfused by the light filtering through the ice, the flat white layer was transformed into an upside-down landscape of blue-green frozen mounds and valleys covered by rolling yellow clouds of algae that were fed on by an infinite army of krill. He paused to adjust the flow of hot water before looking down and seeing a vast green void that faded to black in the depths.

It beckoned, and he dove down to be embraced by it.

The morbid scene slowly revealed itself as if a shadowy curtain had parted as Pitt descended to the bottom. No kelp or coral or brightly colored fish here. He glanced upward at the eerie glow drifting from the ice hole above to orient himself. Then he paused a moment to switch on his dive light and probe it into the wreckage while he equalized his ears.

The remains of the U-boat were broken and scattered. The center hull beneath the conning tower was terribly ruptured and mangled by the explosion from the missile. The tower itself had been blown off the hull and was lying on its side amid a field of debris. The stern appeared attached to the keel by only the propeller shafts. The bow section was twisted but resting upright in the silt. The soft bottom had embraced the wreckage, and Pitt was surprised to see nearly twenty percent of it already buried.

"I've reached the wreck," he announced to Cox. "She's badly broken. I'm going inside the remains."

"Take great care," Cox's disembodied voice came back in Pitt's earpiece. "Cut a hole in your suit from a sharp piece of metal and you'll freeze before you reach the surface."

"Now, there's a cheery thought."

Pitt did not attempt to enter the vessel immediately. He spent nearly ten minutes of precious bottom time swimming over the wreckage and examining the debris field. The warhead had been designed to destroy a much larger target and had left the submarine almost unrecognizable as a seagoing vessel. Pipes and valves and smashed steel plates from the hull lay as if thrown about by a giant hand. He swam over body parts, passing above the grisly remains as if he were a spirit floating over the horrendous aftermath of a terrorist bus bombing.