They had finally reached the bottom, and could make some speed. From behind them, William said, "Watch your head, Munchkin."
"Oops," said Miri, and stopped short. "We got carried away there." This might be a big valley for mice, but just ahead, the walls arched to within inches of each other. She bent down. "It's wider at the bottom. I bet I could wiggle through. I know you could, Juan."
"Maybe," Juan said brusquely. He pushed past her and stepped up into the cleft. He got the active probe off his back, and held it in one hand as he slid into the gap. If he stood sideways and tilted his upper body, he could fit. He didn't even have to take off his jacket. He sidled a foot or two further, dragging the probe gun behind him. Then the passage widened enough for him to turn and walk forward.
Miri followed a moment later. She looked up. "Huh. This is almost like a cave with a hole running along the ceiling."
"I don't like this, Miriam," said William, who was left behind; no way could he squeeze through.
"Don't worry, William. We'll be careful not to get jammed." In any real emergency, they could always punch out a call to 911.
The two kids moved forward another fifteen feet, to where the passage narrowed again, even more than before.
"Caray. The stolen breadcrumb is off the net."
"Maybe we should have just stayed up top and watched."
It was a little late for her to be saying that! Juan surveyed the crumb net. There was not even a hazy guesstimate on the lost node. But there were several pictures from the crumb he had tossed beyond all this: every one of them showed an empty path. "Miri! I don't think the mice ever got to the next viewpoint."
"Hey, did you hear that, William? The mice have taken off down a hole somewhere."
"Okay, I'll look around back here."
Juan and Miri moved back along the passage, looking for bolt-holes. Of course there were no shadows. The fine sand of the path was almost black, the fallen pine needles scarcely brighter. On either side, the rock walls showed dark and mottled red as the sandstone cooled in the night air. "You'd think their nest would show a glow."
"So they're in deep." Miri held up her probe gun, and slipped the radar attachment back onto the barrel. "USMC to the rescue."
They traversed the chamber from one narrowness to the other. When they put the GPR snout of the guns right up to the rock, the lavender echograms were much more detailed than before. There really were tunnels, mouse-sized and extending back into the rock. They went through three batteries in about five minutes, but—"But we still haven't found an entrance!"
"Keep looking. We know there is one."
"Caray, Miri! It's just not here."
"You're right." That was William. He had crawled part way in to look at them. "Come back here. The critters jumped off the trail before it got narrow."
"What? How do you know?"
William backed out, and the kids wriggled out after him. Ol' William had been busy. He had swept the pine cones and needles away from the edges of the path. His little flashlight lay on the ground.
But they didn't need a flashlight to see what William had discovered. The edge of the path, which should have been black and cold, was a dim red, a redness that spread across the rock face like weird, upward-dripping blood.
Miri dropped flat and poked around where the heat red was brightest. "Ha. I got my finger into something! Can't find an end to it." She pulled back ... and a plume of orange followed her hand and then drifted up, its color cooling to red as it swelled and rose above them.
There was the faint smell of burning wood.
For a moment, they just stared at each other, the big black goggle eyes a true reflection of their inner shock.
No more warm air rose from the hole. "We must have found an in-draft," William said.
Both Miri and Juan were on their knees now. They looked carefully, but the goggles didn't have the resolution to let them see the hole clearly—it was simply a spot that glowed a bit redder than anything else.
"Use the gun, Juan."
He probed the rock above the hole and on either side. The tiny passage extended two feet down from the entrance, branching several times before it reached the main network of tunnels and chambers.
"So what happened to the dungball they grabbed? It would be nice to get some pictures from in there."
Juan shrugged, and fed his probe gun still another battery. "They must have it in one of the farther chambers, behind several feet of rock. The crumb doesn't have the power to get through that."
Juan and Miri looked at each other, and laughed. "But we have lots more breadcrumbs!" Juan felt around for the entrance hole and rolled a crumb into it. It lit up about six inches down, just past the first tunnel branch.
"Try another."
Juan studied the tunnel layout for a moment. "If I throw one in just right, I bet I can carom it a couple of feet." The crumb's light disappeared for a moment ... and then appeared as data forwarded via the first one. Yes!
"Still no word from the one they stole," said Miri. There were just the two locator gleams, about six inches and thirty-six inches down their respective tunnels.
Juan touched the gun here and there to the rock face. With the GPR at high power, he could probe through a lot of sandstone. How much could he figure out from what came back? "I think I can refine this even more," he said. Though that would surely make Miri suspicious. "That third fork in the tunnel. Something ... soft ... is blocking it." A brightly reflecting splotch, coming slowly toward them.
"It looks like a mouse."
"Yeah. And it's moving between two breadcrumbs," effectively a two-station wireless tomograph. Maybe I can combine it all. For a moment, Juan's whole universe was the problem of meshing the "breadcrumb tomography" with the GPR backscatter. The image showed more and more detail. He blanked out for a just a second, and for a moment after that forgot to be cautious.
It was a mouse all right. It was facing up the tunnel, toward the entrance the three humans were watching. They could even see its guts, and the harder areas that were skull and ribs and limbs. There was something stuck in its forepaw.
The whole thing looked like some cheap graphics trick. Too bad Miri didn't take it that way. "Okay! I've had it with you, Juan! One person could never work that fast. You doormat! You let Bertie and his committee—"
"Honest, Miri, I did this myself!" said Juan, defending where he should not defend.
"We're getting an F on account of you, and Bertie will own all of this!"
William had been watching with the same detachment as during Miri's earlier accusations. But this time: "I see the picture, Munchkin, but ... I don't think he's lying. I think he did it himself."
"But—"
William turned to Juan, "You're on drugs, aren't you, kid?" he said mildly.
Once a secret is outed—
"No!" Make the accusation look absurd. But Juan floundered, wordless.
For an instant, Miri stared open-mouthed. And then she did something that Juan thought about a lot in the times that followed. She raised her hands, palms out, trying to silence them both.
William smiled gently. "Miriam, don't worry. I don't think Foxwarner is patching us into their summer release. I don't think anyone but us knows what we're saying here at the bottom of a canyon in thick fog."