“Dr. Watson?” said Wang. “You have any other questions?”

“Yes. Is there any disease or toxin that would kill a frog, but not harm a mammal?”

“That’s an interesting question. When it comes to toxins, it would depend on the dose. You give a little arsenic to a frog, you’d kill it. But arsenic would kill a man as well, if he’s given a larger dose. Then again, there are microbial diseases, certain bacteria viruses, that only kill frogs. I’m not a physician, so I’m not absolutely certain they’re harmless to humans, but—”

“Viruses?” she cut in. “Which ones?”

“Well, Ranaviruses, for instance.”

“I’ve never heard of those.”

“Only amphibian experts are familiar with them. They’re DNA viruses. Part of the Iridovirus family. We think they’re the cause of the tadpole edema syndrome. The tadpoles swell up and hemorrhage.”

“And that’s fatal to them?”

“Very much so.”

“Does this virus kill people as well?”

“I don’t know. I don’t think anyone does. I do know Ranaviruses have killed off whole populations of frogs around the world.” The Achilles’ heel, she thought. I’ve found it.

By adding the leopard frog’s DNA to its own genome, Chimera had become part amphibian. It had also acquired an amphibian’s vulnerabilities .

She said, “Is there any way to obtain live samples of one of these Ranaviruses? To test against Chimera?”

There was a long silence. “I get it,” said Dr. Wang. “No one’s tried that yet. No one’s even considered—”

“Can you get the virus?” she cut in.

“Yes. I know two amphibian research labs in California who are working with live Ranaviruses.”

“Then do it. And get hold of Jack McCallum. He needs to know about this.”

“He and Gordon Obie just left for White Sands. I’ll reach them there.”

Tumbleweeds skittered across the road, swept along in a stinging cloud of sand. The men drove past the guardhouse, past the electrified fence, and into the barren Army compound. Jack and Gordon stepped out of the vehicle and squinted up at the sky. The sky was a dusky orange, obscured by windblown dust. The color of sunset, not high noon. They had managed to catch only a few hours of sleep before they’d taken off from Ellington, and it hurt Jack’s eyes just to see the light of day.

“This way, gentlemen,” the driver said.

They followed the soldier into the building.

It was a different reception from the last time Jack had visited.

This time the Army escort was polite and respectful. This time Dr. Isaac Roman was waiting at the front desk, although he did not look particularly happy about their arrival.

“Only you are allowed to come with me, Dr. McCallum,” he said. “Mr. Obie will have to wait here. That was the agreement.

“I made no such agreement,” said Jack.

“Mr. Profitt did, on your behalf. He’s the only reason you’re being allowed in this building. I haven’t a great deal of time, let’s get this over with.” He turned and walked to the elevators.

“Now, there’s your standard Army-issue asshole,” said Gordon.

“Go on. I’ll wait here.”

Jack followed Roman into the elevator.

“First stop is subbasement level two,” said Roman, “where we house our animal trials.” The elevator door opened, and they confronted a wall of glass. It was a viewing window.

Jack approached the window and stared at the laboratory beyond. Inside were a dozen workers wearing biocontamination suits. Cages held spider monkeys and dogs. Right beside the window were glass-enclosed rat cages.

Roman pointed to the rats.

“You’ll notice each cage is labeled with the date and time they were infected. I can think of no better way to illustrate Chimera’s nature.”

In the Day 1 cage, the six rats appeared healthy, vigorously spinning their exercise wheels.

In the cage labeled “Day 2,” the first signs of illness appeared.

Two of the six rats were shivering, their eyes a bright blood-red.

The other four were huddled in a lethargic heap.

“The first two days,” said Dr. Roman, “is Chimera’s reproductive phase. You understand, this is completely opposite to what we see on earth. Usually a life-form must reach maturity before it begins to reproduce. Chimera reproduces first, and then begins to mature. It divides at a rapid rate, producing up to a hundred of itself by forty-eight hours. They start out microscopic in size—not visible to the naked eye. Small enough so that you could breathe them in, or absorb them through your mucous membranes, and not even know you’ve been exposed.”

“So they’re infectious at this early stage in their life cycle?”

“They’re infectious at any stage of their life cycle. They only have to be released into the air. Usually it happens around the time of the victim’s death, or when the corpse bursts open several days post mortem. Once Chimera’s infected you, once it’s multiplied inside your body, each individual copy begins to grow. Begins to develop into…” He paused. “We don’t really know what to them. Egg sacs, I suppose. Because they contain a larval life-form inside them.” Jack’s gaze moved on, to the Day 3 enclosure. All the mice were twitching, limbs thrashing as though repeatedly jolted by electric shocks.

“By the third day,” said Roman, “the larvae are growing rapidly. Displacing the victim’s brain matter by sheer mass effect. Wreaking havoc with the host’s neurologic functions. And by day four…”

They looked at the fourth enclosure. All but one were dead.

The corpses had not been removed, they lay stiff-legged, mouths gaping open. There were still three cages to go, the process of decomposition had been allowed to continue.

By day five, the corpses were beginning to bloat.

On day six, the bellies had grown even larger, the skin stretched drum-taut. viscous fluid seeped from the open eyes and glistened on the nostrils.

And on day seven … Jack halted beside the window, staring into the seventh enclosure.

Ruptured corpses littered the bottom like deflated balloons, the skin torn open to reveal a black stew of dissolved organs. And adhering to one rat’s face was a gelatinous mass of opaque globes.

They were quivering.

“The egg sacs,” said Roman. “By this stage, the corpse’s body cavities are packed with them. They grow at an astonishing rate, feeding on host tissues. Digesting muscles and organs.” He looked at Jack. “Are you familiar with the life cycle of parasitic wasps?

Jack shook his head.

“The adult wasp injects its eggs into a living caterpillar. The larvae grow, ingesting their host’s hemolymph fluid. All this time, caterpillar is alive. Incubating a foreign life-form that’s eating from the inside, until the larvae finally burst out of their dying host.” Roman looked at the dead rats. “These larvae, too, and develop inside a living victim. And that’s what finally kills host. All those larvae, packing into the cranium. Nibbling away the surface of the gray matter. Damaging capillaries, causing intracranial bleeding. The pressure builds. Vessels in the eyes engorge, burst. The host experiences blinding headaches, confusion. He stumbles around as though drunk. In three or four days, he is dead. And still the life-form continues to feed on the corpse. Raiding its DNA. Using that DNA to speed its own evolution.”

“Into what?” Roman looked at Jack. “We don’t know the end point. With every generation, Chimera acquires DNA from its host. The Chimera we’re working with now is not the same one we started out with. Its genome has become more complex. The life-form more advanced.” More and more human, thought Jack.

“This is the reason for absolute secrecy,” said Roman. “Any terrorist, any hostile country, could mine the Galapagos Rift for of these things. This organism, in the wrong hands…” His trailed off.

“So nothing about this thing is manmade.” Roman shook his head. “It was found by chance in the rift. Brought up to the surface by Gabriella. At first Dr. Koenig thought she’d discovered a new species of Archaeons. Instead, what she found was this.” He looked at the wriggling mass of eggs. “A thousand years, they’ve been trapped in the remains of that asteroid. At a depth of nineteen thousand feet. That’s what has kept it in check this time. The fact it came to rest in the deep sea, and not on land.”