"Do they contain nuclear material?" Pitt asked.

"Nuclear material…" Bass repeated, his tone vague. "Is that what you think?"

"The date stated in Vixen 03's flight plan could have put her in the South Pacific in time for the Bikini H-bomb tests. I also found a metal tag on one of the crewmen, marked with the symbol for radioactivity."

"You misread the evidence, Mr. Pitt. True, the canisters were originally designed to house nuclear naval shells. But the night Vylander and his crew disappeared they were used for a far different purpose."

"It's been suggested they're empty."

Bass sat like a wax statue. "If only it were that simple," he murmured. "Unfortunately, there are other instruments of war besides the nuclear kind. You might say that Vixen 03 and her crew were carriers."

"Carriers?"

"A plague," said Bass. "The canisters contain the Doomsday organism."

An uneasy silence settled over the two men as Pitt digested the enormity of the admiral's revelation.

"I see by your expression you are shocked," said Bass.

" 'Doomsday organism,' " Pitt repeated quietly. "It has a terrifying ring of finality about it."

"An apt description, I assure you," said Bass. "Technically speaking, it possessed an impressive-sounding biochemical name that was thirty letters long and quite unpronounceable. The military designation, though, was short and sweet. We simply called it 'QD,' short for 'quick death.' "

"You refer to this 'QD' in the past tense."

The admiral made a helpless gesture.

Force of habit. Until your discovery of Vixen 03, I thought none still existed."

"What exactly was it?"

"QD was the ultimate in sophisticated military weaponry. Thirty-five years ago a microbiologist by the name of Dr. John Vetterly chemically created an artificial form of life that in turn was capable of producing a disease strain that was and still is quite unknown. As simply as I can put it, a nondetectable, unidentifiable bacteriological agent able to incapacitate a living human or animal within seconds of exposure and disrupt the vital body functions, causing death three to five minutes later."

"Won't nerve gas accomplish the same thing?"

"Under ideal conditions, yes. But meteorological disturbances such as wind or storm or extreme temperatures can dilute the lethal dosage of a nerve or toxic agent when it's released over a wide area. An outbreak of QD, on the other hand, can ignore the weather and produce a localized plague that is extremely tenacious."

"But this is the twentieth century. Surely epidemics can be controlled?"

"If the microorganisms can be detected and identified, then it's possible. Decontamination procedures, inoculations with serums and antibiotics, will in most cases slow down or halt a raging epidemic. But nothing on this earth could stop QD once it grabbed a toehold on a city."

"Then how did QD come to be loaded in an aircraft in the middle of the United States?" Pitt demanded.

"Elementary. The Rocky Mountain Arsenal outside of Denver was the nation's primary manufacturer of chemical and biological weapons for over twenty years."

Pitt remained silent and let the old man go on.

Bass looked out at the panorama below, but his eyes were unfocused. "March of fifty-four," he said, as long-buried events began unfolding in his mind. "The H-bomb was set to burst over Bikini. I was placed in command of the QD tests because Dr. Vetterly was funded by the Navy and I was an expert on naval ordnance. I thought it logical at the time to conduct experiments cloaked under the excitement of the nuclear explosion. While the world was concentrating on the main event, we conducted our tests on Rongelo Island, four hundred miles to the northeast, totally unnoticed."

"Rongelo," Pitt said slowly. "The destination of Vixen 03."

Bass nodded. "A raw, bleached knob of coral poking through the sea in the middle of nowhere. Even the birds shy away from it." Bass paused to shift his position on the bench. "I scheduled two series of tests. The first was an aerosol device that scattered a small amount of QD over the atoll. The second included the battleship Wisconsin.

She was to lie back twenty miles and lob a warhead with QD from her main batteries. That test never took place."

"Major Vylander failed to deliver the goods," Pitt surmised.

"The contents of the canisters," Bass acknowledged. "Naval shells armed with QD."

"You could have ordered up another supply."

"I could," Bass agreed. "But the real reason I halted the test series was because of what we learned after the aerosol drop. The results were godawful and filled all who shared in the secret with a feeling of horror."

"You talk as though the island was devastated."

'Wisually, nothing had changed," said Bass, his voice barely audible. "The white sand of the beach, the few palms, all was as it had been. The test animals we had placed on the island were all dead, of course. I insisted on a waiting period of two weeks to give any residual effects a chance to dissipate before permitting the scientists to examine the results first-hand. Dr. Vetterly and three of his assistants landed on the beach wearing full protective clothing and breathing apparatus. Seventeen minutes later, all were dead."

Pitt fought to preserve his balance. "How was it possible?"

"Dr. Vetterly had vastly underestimated his discovery. The potency of other lethal agents wears off after a time. Conversely, QD gains in strength. By what method it penetrated the scientists' protective gear we were never able to determine."

"Did you retrieve the bodies?"

"They still lie there," said Bass with sadness in his eyes. "You see, Mr. Pitt, the terrible power of QD is only half its malignity. QD's most frightening quality is its refusal to die. We later found that its bacillus forms superresistant spores, which are able to penetrate the ground — in Rongelo Island's case, the coral — and live out an astonishing lifespan."

"I find it incredible that after thirty-four years no one can safely go in and carry out Vetterly's remains."

There was a sickness in Bass's voice. "There is no way of pinpointing the exact date," he murmured, "but our best estimate indicated that man won't be able to step foot on Rongelo Island for another three hundred years."

Fawkes leaned over the ship's chart table, studying a set of blueprints, his hand making notations with a pencil. Two large men, well muscled, the faces beneath their hard hats tanned and thoughtful, stood on either side of him. "I want her gutted, every compartment, every scrap of unnecessary tubing and electrical conduits, even her bulkheads."

The man on Fawkes's left snorted derisively. "You've lost your gourd, Captain. Tear out the bulkheads and she'll break up in any sea rougher than a millpond."

"Dugan is right," said the other man. "You can't gut a vessel this size without losing her structural resistance to stress."

"Your objections are duly noted, gentlemen." Fawkes replied. "But in order for her to ride high, her draft must be cut by forty percent."

"I've never heard of gutting a sound ship just to raise her waterline," said Dugan. "What's the purpose of it all?"