After weeks of living in space, they would be weak as kittens, their muscles unable to support them.

The time for separation was approaching. It would take them twenty-five minutes to coast away from ISS and acquire GPS guidance, fifteen minutes for the deorbit burn setup. An hour to land.

In less than two hours, Emma would be back on earth. One way or another.

The thought came before he could suppress it.

Before he could stop himself from remembering the terrible sight of Jill Hewitt’s flayed body on the autopsy table.

He clenched his hands into fists, forcing himself to concentrate on Nicolai Rudenko’s biotelemetry readings. The heart rate was fast but regular, blood pressure holding steady. Come on, come on.

Let’s bring them home now.

He heard Griggs, on board ISS, report, “Capcom, my crew is all aboard the CRV and the hatch is closed. It’s a little cozy in here, we’re ready when you are.”

“Stand by to power up,” said Capcom.

“Standing by.”

“How is the patient doing?” Jack’s heart gave a leap as he heard Emma’s voice join the loop.

“His vitals remain stable, but he’s disoriented times three. The crepitus has migrated to his neck and upper torso, and it’s given him some discomfort. I’ve given him another dose of morphine.” The sudden decompression had caused air bubbles to form in his soft tissues. The condition was harmless, but painful. What Emma worried about were air bubbles in the nervous system. Could that be the reason Nicolai was confused?

Woody Ellis said, “Go for power up. Remove ECCLES seals.”

“ISS,” said Capcom, “you are now go for—”

“Belay that!” a voice cut in.

Jack looked at Flight Director Ellis in confusion. Ellis looked just as confused. He turned to face JSC director Ken Blankenship, who’d just walked into the room, accompanied by a dark-haired man in a suit and a half dozen Air Force officers.

“I’m sorry, Woody,” said Blankenship. “Believe me, this is not my decision.”

“What decision?” said Ellis.

“The evacuation is off.”

“We have a sick man up there! The CRV’s ready to go—”

“He can’t come home.”

“Whose decision is that?”

The dark-haired man stepped forward. He said, with what was almost a quiet note of apology, “The decision is mine. I’m Jared Profitt, White House Security Council. Please tell your crew to reopen the hatches and exit the CRV.”

“My crew is in trouble,” said Ellis. “I’m bringing them home.”

Trajectory cut in, “Flight, we have to go to sep now if we want them landing on target.”

Ellis nodded to Capcom. “Proceed to CRV power up. Let’s go to sep.” Before Capcom could utter another word, his headset was yanked off and he was hauled from his chair and pushed aside. An Air Force officer took Capcom’s place at the console.

“Hey!” yelled Ellis. “Hey!” All the flight controllers froze as the other Air Force officers immediately fanned out across the room. Not a weapon was drawn, but the threat was apparent.

“ISS, do not power up,” said the new Capcom. “The evacuation has been canceled. Reopen the hatches and exit the CRV.”

A baffled Griggs responded, “I don’t think I copied that, Houston.”

“The evacuation is off. Exit the CRV. We are experiencing difficulties with both TOPO and GNC computers. Flight has decided it’s best to hold off the evac.”

“How long?”

“Indefinitely.” Jack shot to his feet, ready to wrestle away Capcom’s headset.

Jared Profitt suddenly stepped in front of him, barring his way.

“You don’t understand the situation, sir.”

“My wife is on that station. We’re bringing her home.”

“They can’t come home. They may all be infected.”

“With what?” Profitt didn’t answer.

In fury, Jack lunged toward him, but was hauled back by two Air Force officers.

“Infected with what?” Jack yelled.

“A new organism,” said Profitt. “A chimera.”

Jack looked at Blankenship’s stricken face. He looked at the Air Force officers who now stood poised to assume control of the consoles. Then he noticed another familiar face, that of Leroy Cornell, who’d just come into the room.

Cornell looked pale and shaken.

That’s when Jack understood that this decision had been made at the very top. That nothing he, or Blankenship, or Woody Ellis would make a difference.

NASA was no longer in control.

The Chimera

August 13

They gathered at Jack’s house, where all the shades were drawn.

They didn’t dare meet at JSC, where they would most certainly be noticed. They were all so stunned by the sudden takeover of NASA operations they had no idea how to proceed. This was one crisis which they had no operations manual, no contingency plans. Jack had invited only a handful of people, all of them from inside NASA operations, Todd Cutler, Gordon Obie, Flight Directors Woody Ellis and Randy Carpenter, and Liz Gianni from the Payload Directorate.

The doorbell rang, and everyone tensed.

“He’s here,” said Jack, and he opened the door.

Dr. Eli Petrovitch from NASA’s Life Sciences Directorate stepped in, clutching a laptop carrying case. He was a thin and fragile man who, for the past two years, had been battling Lymphoma. Clearly he was losing the war. Most of his hair had fallen out, and only a few brittle white strands remained. His skin like yellowed parchment, stretched over the jutting bones of his face. But there was the glow of excitement in his eyes, lit by a scientist’s unflagging curiosity.

“Did we get it?” asked Jack.

Petrovitch nodded and patted his briefoase. On that skeletal face, his smile looked ghoulish. “USAMRIID has agreed to share some of its data.”

“Some?”

“Not all. Much of the genome remains classified. We were given only parts of the sequence, with large gaps. They’re given us just enough to prove that the situation is grave.” He carried a laptop to the dining room table and flipped it open. As everyone crowded around to watch, Petrovitch booted up the computer, then slipped in a floppy disk.

Data began to scroll down, line after line of seemingly random letters marching at a dizzying pace down the screen. It was not text, these letters did not spell out words at all, but a code. The four letters reappeared again and again, in a changing sequence, A, T, G, and C. They represented the nucleotides adenine, thymine, guanine, and cytosine. The building blocks that made up DNA. string of letters was a genome, the chemical blueprint for a organism.

“This,” said Petrovitch, “is their chimera. The organism that killed Kenichi Hirai.”

“What is this ky-mir-ra’ thing I keep hearing about?” asked Randy Carpenter. “For the sake of us ignorant engineers, maybe you could explain it?”

“Certainly,” said Petrovitch. “And there’s no reason to feel ignorant. It’s not a term used much outside of molecular biology. The word comes from the ancient Greeks. Chimera was a mythological beast, said to be unconquerable. A fire-breathing creature with a lion’s head, a goat’s body, and a serpent’s tail. She was eventually slain by a hero named Bellerophon. It wasn’t exactly a fight, because he cheated. He hitched a ride on Pegasus, the horse, and shot arrows down at Chimera from above.”

“This mythology is interesting,” cut in Carpenter impatiently, “but what’s the relevance?”

“The Greek Chimera was a bizarre creature made up of three different animals. Lion, goat, and serpent, all combined into one. And that’s exactly what we’re seeing here, in this chromosome. A creature as bizarre as the beast killed by Bellerophon. This is a biological chimera whose DNA comes from at least three unrelated species.”

“Can you identify those species?” asked Carpenter.

Petrovitch nodded. “Over the years, scientists around the world have amassed a library of gene sequences from a variety of species, from viruses to elephants. But collecting this data is slow and tedious. It’s taken decades just to analyze the human genome. So you can imagine, there are a number of species that haven’t been sequenced. Large areas of this chimera’s genome can’t be identified, they’re nowhere in the library. But here’s what we have been able to identify so far.” He clicked on the icon for “species matches.” On the screen appeared, Mus musculis common mouse), Rana pipiens (northern leopard frog), Homo sapiens.