Dr. Gunn’s voice took on the tone of a parental lecture. “I would like you to show me the symbio prototype.”

Isaac was taller than Dr. Gunn, but there was something about the man’s presence that made him hunch over, making himself smaller, as if in apology. At a fridge he withdrew a specimen jar that contained a slimy green tangle, like something pulled from a clogged drain. He held it up and the muck slithered from one side of the glass to the other. Then it whipped a tendril toward the cap and dragged itself up and out of sight.

“I’ve been reviewing your lab reports and it appears that the prototype fails in most of its hosts.”

“Yes. That’s the thing. We’re not sure what makes for a good match yet. Whether it’s blood type or some genetic marker or—”

“Excellent,” Dr. Gunn said. “Now, follow me, please.”

They departed the laboratory together. The rest of the scientists studied them in silence.

Isaac and Dr. Gunn spent the next ten minutes moving through security locks and taking elevators that required key cards until they came to a series of cells. “Wow. I’ve never been down here,” Isaac said. “I didn’t even know these existed.”

“Now you know,” Dr. Gunn said. He walked swiftly for someone with such short legs.

The cells were made of glass, not metal, and brightly lit. One of them was smeared with black mold. Another fluttered with moths with red eyes on their wings. Another held a man with skin that appeared gray and cracked and elephant-like, and as they passed by, he peeled off a long dry strip from his arm and ate it. Another contained a teenage girl with purple-flowered branches growing out of her heels and knees and spine and elbows and shoulders. In the last they found a man who appeared to be dead. Flowering vines spilled out of his open mouth and reached across the floor and along the wall, splitting into smaller and smaller shoots like green capillaries.

“Oh, shit,” Isaac said as Dr. Gunn trained his eyes on him. “Oh, shit, sir. What happened to him?”

“What happened to him? He died. He’s compost. That’s what happened to him.”

“Right. But . . .”

Dr. Gunn gestured at the body and said, “This is a member of the Iranian military. He parachuted onto an American naval vessel in the Persian Gulf and killed twenty men before he was overpowered and detained. Do you understand what that means?”

“I—no.”

“It means Iran has developed its own symbiote.”

“Oh. Damn. Wow.”

“This soldier was shot ten times. We tried to keep him alive. Unsuccessfully. And now—as you can see—the floronic half of him remains our prisoner. It’s like a garden without a proper patch of dirt in there.”

“That’s good news, then. I can take some samples off him and—”