“So, Jem,” Uncle Joe said. He put down his coffee cup and patted his lips with a paper napkin left over from Halloween; it was black with orange jack-o’-lanterns and white ghosts on it. “Um . . . how far can you . . . er . . . you know, when your sister’s not with you?”

“How far?” Jem said uncertainly, and looked at Mam. It hadn’t ever occurred to him to wonder.

“If you went in the living room right now,” Uncle Joe said, nodding at the door. “Could you tell she was in here, even if you didn’t know she was in here?”

“Yeah. I mean, yes, sir. I think so.” He stuck his finger in the hot chocolate: still too hot to drink. “When I was in the tunnel, in the train—I knew she was . . . somewhere. It’s not like science fiction or anything, I mean,” he added, trying to explain. “Not like X-rays or phasers or like that. I just . . .” He struggled for an explanation and finally jerked his head at Mam, who was staring at him with a serious kind of look that bothered him a little. “I mean, if you closed your eyes, you’d still know Mam was here, wouldn’t you? It’s like that.”

Mam and Uncle Joe looked at each other.

“Want toast?” Mandy thrust her half-gnawed piece of buttered toast at him. He took it and had a bite; it was good, squidgy white bread, not the home-baked brown kind Mam made, with gritty bits in it.

“If he could hear her—sense her—from the tunnel while she was at home, he can do it for a good long way,” Mam said. “But I don’t know for sure that she was at home then—I was driving all over with her, looking for Jem. And Mandy could sense him while we were in the car that night. But—” Now her eyebrows went together. He didn’t like seeing a line there. “She was telling me she was getting colder, when we drove toward Inverness, but I don’t know if she meant she couldn’t hear him at all, or . . .”

“I don’t think I can feel her when I’m at school,” Jem said, anxious to be helpful. “But I’m not sure, ’cause I don’t think about her at school.”

“How far’s the school from your place?” Uncle Joe asked. “You want a Pop-Tart, princess?”

“Yes!” Mandy’s buttery round face lighted up, but Jem glanced at Mam. Mam looked as if she wanted to kick Uncle Joe under the counter for a second, but then she glanced down at Mandy and her face went all soft.

“All right,” she said, and Jem felt a fluttery, excited sort of feeling in his middle. Mam was telling Uncle Joe how far the school was, but Jem wasn’t paying attention. They were going to do it. They were really going to do it!

Because the only reason Mam would let Mandy eat Pop-Tarts without a fuss was because she figured she’d never get to eat another one.

“Can I have one, too, Uncle Joe?” he asked. “I like the blueberry ones.”

THE WALL

HADRIAN’S WALL looked very much as Roger recalled it from a long-ago school trip. A huge thing, standing nearly fifteen feet high and eight feet wide, double stone walls filled with rubble in between, winding off into the distance.

The people were not that much different, either—at least in terms of speech and livelihood. They raised cattle and goats, and the Northumberland dialect had apparently not developed much since Geoffrey Chaucer’s time. Roger and Buck’s Highland accents elicited slit-eyed looks of suspicious incomprehension, and they were for the most part reduced to basic gestures and sign language in order to obtain food and—occasionally—shelter.

With a bit of trial and error, Roger did work out an approximate Middle English for “Hast come here a stranger?” From the looks of the place—and the looks he and Buck were getting—he would have said the contingency was remote, and so it proved. Three days of walking, and they were still plainly the strangest men anyone near the wall had ever seen.

“Surely a man dressed in RAF uniform would look even more peculiar than we do?” he said to Buck.

“He would,” Buck replied logically, “if he was still wearing it.”

Roger grunted in chagrin. He hadn’t thought of the possibility that Jerry might have discarded his uniform on purpose—or been deprived of it by whomever came across him first.

It was on the fourth day—the wall itself had rather surprisingly changed, being no longer built of stone and rubble but of stacked turves—that they met a man wearing Jerry MacKenzie’s flight jacket.

The man was standing at the edge of a half-plowed field, staring morosely into the distance, apparently with nothing on his mind save his hair. Roger froze, hand on Buck’s arm, compelling him to look.

“Jesus,” Buck whispered, grabbing Roger’s hand. “I didn’t believe it. That’s it! Isn’t it?” he asked, turning to Roger, brows raised. “I mean—the way ye described it . . .”

“Yes. It is.” Roger felt his throat tighten with excitement—and fear. But there was only the one thing to be done, regardless, and, dropping Buck’s hand, he forged through the dead grass and scattered rock toward the farmer, if that’s what he was.

The man heard them coming and turned casually—then stiffened, seeing them, and looked wildly round for help.

“Eevis!” he shouted, or so Roger thought. Looking over his shoulder, Roger saw the stone walls of a house, evidently built into the wall.

“Put up your hands,” Roger said to Buck, throwing up his own, palm out, to show his lack of threat. They advanced slowly, hands up, and the farmer stood his ground, though watching them as though they might explode if they got too close.

Roger smiled at the man and elbowed Buck in the ribs to make him do likewise.

“Gud morn,” he said clearly and carefully. “Hast cum a stranger here?” He pointed to his own coat—and then to the flight jacket. His heart was thumping hard; he wanted to knock the man over and strip it off his back, but that wouldn’t do.

“Naow!” said the man quickly, backing away, holding on to the edges of the jacket. “Begone!”

“We mean ye no harm, daftie,” Buck said, in as conciliating a tone as he could manage. He patted the air in a soothing manner. “Kenst du dee mann . . . ?”

“What the bloody hell is that?” Roger asked, out of the side of his mouth. “Ancient Norse?”

“I don’t know, but I heard an Orkneyman say it once. It means—”

“I can tell what it means. Does this look like Orkney to you?”

“No. But if you can tell what it means, maybe he can, too, aye?”

“Naow!” the man repeated, and bellowed, “EEVIS!” again. He began to back away from them.

“Wait!” said Roger. “Look.” He fumbled quickly in his pocket and withdrew the little oilcloth packet holding his father’s identity disks. He pulled them out, dangling them in the chilly breeze. “See? Where is the man who wore these?”

The farmer’s eyes bulged, and he turned and ran clumsily, his clogs hindering him through the clods of the field, shouting, “Eevis! Hellup!” and several other, less comprehensible things.

“Do we want to wait for Eevis to turn up?” Buck said, shifting uneasily. “He may not be friendly.”

“Yes, we do,” Roger said firmly. The blood was high in his chest and face, and he flexed his hands nervously. Close. They were so close—and yet . . . his spirits went from exhilaration to plunging fear and back within seconds. It hadn’t escaped him that there was a strong possibility that Jerry MacKenzie had been killed for that jacket—a possibility that seemed much more likely in view of their interlocutor’s precipitate flight.

The man had disappeared into a windbreak of small trees, beyond which some sheds were visible. Perhaps Eevis was a stockman or dairyman?

Then the barking started.

Buck turned to look at Roger.

“Eevis, ye think?”

“Jesus Christ!”

A huge, broad-headed, barrel-chested brown dog with a broad, toothy jaw to match came galloping out of the trees and made for them, its proprietor bringing up the rear with a spade.

They ran for it, circling the house with Eevis on their heels, baying for blood. The broad green bank of the wall loomed up in front of Roger and he leapt for it, jamming the toes of his boots into the turf and scrabbling with fingers, knees, elbows—and likely his teeth, too. He hurled himself over the top and bounced down the far side, landing with a tooth-rattling thud. He was fighting to draw breath when Buck landed on top of him.

“Shit,” his ancestor said briefly, rolling off him. “Come on!” He jerked Roger to his feet and they ran, hearing the farmer shouting curses at them from the top of the wall.

They found refuge in the lee of a crag a few hundred yards beyond the wall and collapsed there, gasping.

“The Emp . . . Emperor Had . . . rian kent what the blood . . . y hell he . . . was about,” Roger managed, at last.

Buck nodded, wiping sweat from his face. “No . . . very hospitable,” he wheezed. He shook his head and gulped air. “What . . . now?”

Roger patted the air, indicating the need for oxygen before he could formulate ideas, and they sat quiet for a bit, breathing. Roger tried to be logical about it, though spikes of adrenaline kept interfering with his thought processes.

One: Jerry MacKenzie had been here. That was all but certain; it was beyond the bounds of probability that there should be two displaced travelers wearing RAF flight jackets.

Two: he wasn’t here now. Could that be safely deduced? No, Roger concluded reluctantly, it couldn’t. He might have traded the jacket to Eevis’s owner for food or something, in which case he’d likely moved on. But if that were the case, why had the farmer not simply said so, rather than setting the dog on them?

And if he’d stolen the jacket . . . either Jerry was dead and buried somewhere nearby—that thought made Roger’s stomach clench and the hairs prickle on his jaw—or he’d been assaulted and stripped but perhaps had escaped.

All right. If Jerry was here, he was dead. And if so, the only way of finding out was to subdue the dog and then beat the information out of Eevis’s owner. He didn’t feel quite up to it at the moment.

“He’s not here,” Roger said hoarsely. His breathing was still hard, but regular now.

Buck gave him a quick look, but then nodded. There was a long streak of muddy green down his cheek, smeared moss from the wall that echoed the green of his eyes.

“Aye. What next, then?”

The sweat was cooling on Roger’s neck; he wiped it absently with the end of the scarf that had somehow made it over the wall with him.

“I’ve got an idea. Given the reaction of our friend there”—he nodded in the direction of the farmstead, invisible beyond the green mass of the wall—“I’m thinking that asking for a stranger might be not the wisest thing. But what about the stones?”

Buck blinked at him in incomprehension.

“Stones?”

“Aye. Standing stones. Jerry did travel, we ken that much. What’re the odds he came through a circle? And if so . . . they’re likely none so far away. And folk wouldn’t be threatened, I think, by two dafties asking after stones. If we find the place he likely came through, then we can start to cast out from there and ask at the places nearest to the stones. Cautiously.”

Buck tapped his fingers on his knee, considering, then nodded.

“A standing stone isna like to bite the arses out of our breeks. All right, then; let’s go.”

RADAR

Boston

December 9, 1980

JEM FELT NERVOUS. Mam and Uncle Joe were both trying to act as if everything was okay, but even Mandy could tell something was up; she was squirming around in the backseat of Uncle Joe’s Cadillac like she had ants in her pants, pulling up her buttoned sweater over her head so her black curls fluffed out of the neckhole like something boiling over.

“Sit still,” he muttered to her, but he didn’t expect her to, and she didn’t.

Uncle Joe was driving, and Mam had a map open in her lap. “What are you doing, Mandy?” Mam said absently. She was making marks on the map with a pencil.

Mandy unbuckled her seat belt and popped up on her knees. She’d pulled her arms out of her sweater so they flopped around, and now just her face was poking out of the neckhole.

“I’m an ottopus!” she said, and shook herself so the sweater’s arms danced. Jem laughed, in spite of himself. So did Mam, but she waved Mandy back down.

“Octopus,” she said. “And put your seat belt back on right now. Octo means eight in Latin,” she added. “Octopuses have eight legs. Or arms, maybe.”

“You’ve only got four,” Jem said to Mandy. “Does that make her a tetrapus, Mam?”

“Maybe.” But Mam had gone back to her map. “The Common, do you think?” she said to Uncle Joe. “It’s a little more than a quarter mile across the longest axis. And we could go down into the Public Garden, if . . .”

“Yeah, good idea. I’ll let you and Jem off on Park Street, then drive along Beacon to the end of the Common and back around.”

It was cold and cloudy, with just a few flakes of snow in the air. He remembered Boston Common and was kind of glad to see it again, even with the trees leafless and the grass brown and dead. There were still people there; there always were, and their winter hats and scarves looked happy, all different colors.

The car stopped on Park Street, across from the tourist trolleys that stopped every twenty minutes. Dad had taken them all on one once—one of the orange ones, with the open sides. It had been summer then.

“Do you have your mittens, sweetheart?” Mam was already out on the sidewalk, peering through the window. “You stay with Uncle Joe, Mandy—just for a few minutes.”

Jem got out and stood with Mam on the sidewalk, putting on his mittens while they watched the gray Caddy pull away.