The Apocalypse Troll

"Dick." He squeezed back, then nodded to Hastings. "You know Jayne Hastings, I think?"

"We've met." Aston extended his hand to the lieutenant commander in turn. She smiled, but her green eyes burned behind her glasses.

"All right, folks," Aston continued more briskly, "before we do anything else, we need to see your EEGs."

"Dick, what the-"

"Bear with me, M&M," Aston said softly, and Morris was surprised by the almost entreating note in his powerful voice. That silenced him, and he opened his briefcase and dragged out several folded sheets of paper.

"All right, Dick," he sighed. "Here. And Admiral McLain figured it might be as well to send his along, too."

"He did? Four-oh!" Aston exclaimed. "I knew you were a persuasive bastard!" He took the EEGs and, to Morris's surprise (though why anything should surprise him at this point eluded him), handed them to the girl. "Here, Milla," he said, and Morris made his eyebrows stay put despite the odd gentleness in Dick's voice. Could he-? No! It was preposterous.

The girl sat cross-legged on the bed and spread the charts over her lap. She looked like a Girl Scout practicing origami, Morris thought, but her smooth young face was intent. She ran a rosy fingertip across the first graph, clearly searching for something, then set it aside to check the second. Then the third. She looked up at Aston and drew a deep breath, her eyes brightening with what could only be relief, as she nodded.

"Clean sweep," she said softly. "All three of them."

"Thank God," Aston murmured reverently, and sank into the chair by the bed. Morris stared at him in consternation as he rubbed his bald head. It was a gesture Morris had seen often, but Aston's rock-steady fingers had never trembled before, not even after the firefight in Amman.

"Dick?" His friend's reaction had banished his last frustration. The pressure under which this ill-assorted pair labored was too obvious.

"Sorry, Mordecai." Aston shook his head and managed a tired smile. "You'll be pleased to know that you two-and Admiral McLain-belong to a select group. One cleared for the whole story, as it were. Sit down."

He gestured at the extra chairs crowding the small compartment, and the intelligence officers sat wordlessly, staring first at each other and then at him.

"People," he said slowly, "we've been invaded." He saw their shoulders stiffen and gri

He had their undivided attention, and the absurdity of the situation appealed to his sense of humor. He repressed an exhaustion-spawned urge to giggle and cleared his throat, instead.

"Commander Morris, Lieutenant Commander Hastings, allow me to introduce the good guys," he said, waving a hand at Ludmilla. "This is Colonel Ludmilla Leonovna, people-not a Russian," he added quickly, seeing the same initial assumption in both pairs of eyes and remembering his own first reaction. Amusement strengthened his voice. "Not even a Terran, really. You see, she comes from Sigma Draconis... ."

" ... so that's the story," Aston finished three hours later, and the intelligence officers shook their heads in unison. The tale he and Ludmilla had told was incredible, preposterous, impossible to believe ... and carried the unmistakable ring of truth.

"Dear God," Morris said softly, speaking for the first time in over half an hour. "Dear sweet God in Heaven."

"Amen," Hastings said, equally softly, but there was worry in her eyes. She rubbed the tip of her nose gently for several seconds, then glanced sharply at Ludmilla.

"Excuse me, Colonel-" she began.

"Please, Ludmilla. Or Milla," Ludmilla interrupted.

"All right, Ludmilla," Hastings agreed. "But I've got two burning questions for you."

"Only two?" Ludmilla asked with a crooked smile.

"Two immediate ones," Hastings acknowledged with a shadow of an answering smile. "First, and most pressingly, there's the matter of this symbiote of yours. You say it's transmitted by direct blood transfer?"

"Yes."

"Then I think we have a problem," Hastings said softly. "Possibly a very serious one." Ludmilla raised an eyebrow, inviting her to continue. "Mosquitoes," Hastings said softly, and felt Morris stiffen beside her.

"Don't worry," Ludmilla said quickly. "Believe me, the Normals of my own time worried about the same thing, but we never found a single instance of transmission by any insect or vermin vector."

"Why not?" Hastings asked sharply.

"Two reasons," Ludmilla replied imperturbably. "First, our symbiotes don't seem to approve of insect bites; they exude a sort of natural insect repellent. But the second reason is even more effective. It takes the average human a little less than twelve hours to go into crisis if she's infected with the symbiote, but it acts a lot faster on smaller life forms and none of them survive. Any bug that bites me will be dead before it gets its proboscis out of my bloodstream. It'll never live long enough to transmit it to anyone else."

"Oh." Hastings mulled that over for a moment, then nodded slowly. "But what about insects on your home planet?" she asked curiously. "If they're immune because of their different amino acids ... ?"

"Commander Hastings," Ludmilla said gently, "one of Midgard's main tourist attractions is that the local insects don't like the taste of humans."

"That would be an attraction," Hastings agreed with a smile, and Ludmilla felt her spirits rise. That smile carried acceptance as well as amusement. For a moment, she'd been afraid Hastings was going to turn paranoid on her. She'd seen too many people of her own time do exactly the same, and with far less reason.

"But you said you had a second question?" she prompted after a minute.

"Oh, yes! I don't pretend to be an expert, but it occurs to me that this whole thing represents a causal nightmare."

"I couldn't agree more," Ludmilla said sincerely.

"Well, if we accept causality at all, then it sounds to me like we're faced with the disagreement between the Copenhagen school and the Many-Worlds interpretation," Hastings said. "The whole question of what happens when the superposition collapses and-"

"Jayne," Morris said sternly, "I've warned you about talking gibberish."

"Oh, hush, Mordecai!" his disrespectful junior shot back, but she paused. "All right, in simple terms the problem is how Colonel Leonovna-Ludmilla-and this Troll creature can change their own past. On the face of it, the very notion negates the entire concept of causality."

"The old 'can I kill my grandfather' thing?" Morris mused.

"More or less. The point is, what's happening represents a significant alteration to history. Ludmilla, did your records contain any mention of what happened to Task Force Twenty-Three?"

"No. And my hobby interest was military history. If there'd been any record of an authenticated attack on any Terran military force by UFOs, I'd've known about it, believe me."

"So we already have a gross shift in your history," Hastings pointed out. "Presumably, the effort we'll have to mobilize to do anything effective about this Troll will have an even greater effect. If nothing else, we know these Kanga creatures exist." She smiled unpleasantly. "Knowing that, I think we can confidently assume that their reception will be even more energetic than it 'was' in your own past. But the end result will be that your universe will never come into existence at all!"

"I know," Ludmilla said softly.

"But if it doesn't, then you won't come back, and if you don't come back, then it will," Morris said slowly, rubbing his forehead as he tried to understand. "What do we have here-some kind of loop?"