Dahlgren slowly backed away from the aircraft, then called Dirk on the radiophone.

“Say, old buddy, I've got the business end of one of the float planes here, but it doesn't look like she had any weapons mounted when she sank. Airman Skully sends his regards, though.”

“I've found the remains of the second plane and she's clean as well,” Dirk replied. “Meet me at the conning tower.”

Dirk had found the second bomber lying thirty yards away from the sub, flipped over on its back. The two large pontoons had been ripped off the Seiran bomber when the sub went under, and the plane's fuselage, with wings still attached, had fluttered down to the bottom. He could easily see that no ordinance was mounted on the undercarriage and found no evidence that a bomb or torpedo had fallen away when the plane sank.

Swimming back to the sub's topside deck, he followed the eighty-five-foot-long catapult ramp along the bow until reaching a large round hatch. The vertical hatch capped the end of a large twelve-foot-diameter tube, which was mounted at the base of the conning tower and stretched aft for more than one hundred feet. The airtight tube had been the hangar for the Seiran aircraft, storing the sectional pieces of the planes until they were ready for launching. Set back above the tubular section was a small platform containing triple-mounted 25mm antiaircraft guns, which still sat with their barrels pointed skyward waiting for an unseen enemy.

Instead of a large metal sail rising upward, Dirk found a huge hole in the center of the I-403, the gaping remains of where the conning tower had been sheared off in the collision. A small school of ling-cod swam around the jagged crater's edge, feeding on smaller marine life and adding a splash of color to the dark scene.

“Wow, you could drive your Chrysler through that hole,” Dahlgren remarked as he swam up alongside Dirk and surveyed the crater.

“With change to spare. She must have gone down in a hurry when the sail ripped off.” The two men silently visualized the violent collision between the two war vessels so many years before and imagined the agony of the helpless crew of the I-403 as the submarine sank to the bottom.

“Jack, why don't you take a pass through the hangar and see if you can eyeball any ordnance,” Dirk said, pointing a gloved hand toward a gash along the top of the aircraft hangar. “I'll go belowdecks and do the same.”

Dirk glanced at the orange face of his Doxa dive watch, a gift from his father on his last birthday. “We've only got eight more minutes of bottom time. Let's be quick.”

“I'll meet you back here in six,” Dahlgren said, then disappeared with a kick of his fins through the gash in the hangar wall.

Dirk entered the gloomy crevice adjacent to the hangar, diving past a jagged edge of mangled and twisted steel. As he descended, he could make out the sub's unusual twin side-by-side pressured hulls, which ran lengthwise down the keel. He entered an open bay and quickly identified it as the remains of the control room, as evidenced by a large mounted helm's wheel, now covered in barnacles. An array of radio equipment was fixed to one side of the room-while an assortment of mechanical levers and controls protruded from another wall and ceiling. Shining his light on one set of valves, he made out barasuto tanku in white lettering, which he presumed operated the ballast tanks.

Kicking his fins gently, Dirk moved forward at a deliberate pace trying not to stir up sediment from the deck. As he passed from one compartment to the next, the submarine seemed to echo with the life from the Japanese sailors. Dining plates and silverware were strewn across the floor of a small galley. Porcelain sake vials were still standing in cabin shelves. Gliding into a large wardroom where officers' staterooms lined one side, Dirk admired a small Shinto shrine mounted on one wall.

He continued forward, cognizant of his dwindling bottom time but careful to take in all that his eyes could absorb. Moving past a maze of pipes, wires, and hydraulic lines, he reached the chief's quarters, near the forward part of the ship. At last, he approached his objective, the forward torpedo room, which loomed just ahead. Thrusting ahead with a powerful scissors kick, he advanced to the torpedo room entrance and prepared to pass in. Then he stopped dead in his tracks.

He blinked hard, wondering if his eyes were playing tricks on him. Then he turned off his light and looked through the hatch again. He was not imagining what he saw.

In the inky bowels of the rusting warship, entombed at the bottom of the sea for over sixty years, Dirk was welcomed by a faint but distinct flashing green light.

Dirk pulled himself through the hatch and into the pitch-black darkness of the torpedo room, save for the penetrating beam of light. As his eyes adjusted to the blackness, the flashing green light became clearer. It appeared to be a pair of tiny lights, situated at eye level, and fixed at the far side of the room.

Dirk turned his own light back on and surveyed the room. He was in the upper torpedo room, one of two torpedo bays the I-403 had stacked vertically at the bow of the sub. Near the forward bulkhead, he could see the round chamber hatches for the four twenty-one-inch-diameter torpedo tubes. Lying in racks on either side of the room were six of the huge Type 95 torpedoes, large and deadly fish that were both more reliable and more explosive than the American counterpart during the war. Jumbled on the floor, Dirk shined his light on two additional torpedoes that had been jarred out of their racks when the submarine had slammed into the bottom. One torpedo lay flat on the floor, its nose angled slightly off bow from where it had rolled after hitting the deck. The second torpedo was propped on some debris near its tip, pointing its nose lazily upward. It was just above this second torpedo where the eerie green light flashed on and off.

Dirk floated over to the pulsating light, putting his face mask up close to the mystery beam. It was nothing more than a small stick-on digital clock wedged at the end of the torpedo rack. Fluorescent green block numbers flashed a row of zeroes, indicating an elapsed time that had run out more than twenty-four hours before. Days, weeks, or months before, it would be impossible to tell. But it certainly could not have been placed there sixty years earlier.

Dirk plucked the plastic clock and stuffed it in a pocket of his BC, then peered upward. His expended air bubbles were not gathering at the ceiling, as expected, but were trailing upward and through a shaft of pale light. He kicked up with his fins and found that a large hatch to the open deck had been wedged open several feet, easily allowing a diver access to and from the torpedo bay.

A crackly voice suddenly burst through his earpiece. “Dirk, where are you? It's time to go upstairs,” Dahlgren's voice barked.

“I'm in the forward torpedo room. Come meet me on the bow, I need another minute.”

Dirk looked at his watch, noting that their eight minutes of bottom time had expired, then swam back down to the torpedo rack.

Two wooden crates were crushed beneath one of the fallen torpedoes, split open like a pair of suitcases. Constructed of hardwood mahogany, the crates had amazingly survived the ravages of salt water and microorganisms and were in a minimal state of decay. He curiously noted that no silt covered the broken crates, unlike every other object he had seen on the submarine. Someone had recently fanned away the sediment to reveal the crates' contents.

Dirk swam over to the closest crate and looked inside. Like a half carton of eggs, six silver aerial bombs were lined up in a custom-fitted casemate. Each bomb was nearly three feet long and sausage-shaped, with a fin-winged tail. Half of the bombs were still wedged under the torpedo, but all six had been broken up by the torpedo's fall. Oddly, to Dirk, they appeared to be cracked rather than simply crushed. Running his hand over an undamaged section of one of the bombs, he was surprised to feel the surface had a glassy smoothness to the touch.