The rear scanner showed a big blip approaching fast, and the readout had its speed at Mach 1.3 and decelerating. He'd be on us in twenty seconds. The balloon didn't register at all.
"Sam, give it all you got," I said.
"I'm givin' it."
Suddenly, the blip started veering off. It swooped off to our left for a few seconds, then began wobbling, its speed dropping greatly. It appeared to be disoriented, unsure.
"I think I can see him," Roland said, peering through his port out into the twilight. "He's pacing us. It's as if he can't see us. Remarkable."
From the rear came a dim greenish glow as Carl launched another balloon in the Roadbug's general direction. I took my eyes from the scanner for a moment to watch it scoot outward. Carl was about three hundred meters behind us now.
The blip drifted away from us, describing a meandering arc. Carl fired another balloon after it for good measure.
"Carl, old pal, old buddy," I said, "you have done what nobody in the known universe has ever managed to do. You told a Bug to go punk-off."
"Yeah, get lost, ya asshole!"
"Bugger off, Bug!" Sean contributed.
"Okay," I said. "I'm for getting off this cue ball immediately. Let's turn back toward that near portal and shoot the motherpunker right now. Carl, get yourself up here and take point so we… Oh hell."
Another blip was vectoring toward us from the left. No problem, really; Carl fired another balloon at it, producing almost the same effect. This Bug, however, didn't drift off. It continued to close with us, albeit slowly, effectively blocking us from turning toward the portal. By that time the first Bug was cautiously approaching again, having seemed to recover control of itself. Carl fired again to the right, but this time the first Bug dropped back suddenly, apparently waiting for the balloon to drift out of range. We continued like this for several kilometers, running as hard as we could while keeping the Bugs at a safe distance. Either the Bugs did not have long-range weapons or were not using them for some reason. More blips appeared on our screens. Word seemed to have gotten out about us. The Bugs kept pace with us, paralleling our course but keeping at a prudent distance. Occasionally one would swoop in daringly near, then scamper away.
"What do we do now?" Carl asked glumly.
"Find a portal right quick," I answered. "I get the feeling they're herding us toward something, but I don't see a portal in the direction we're heading."
"Let's change course then."
"Okay. Turn right forty-five degrees. Acknowledge."
"Right forty-five degrees, roger."
We turned and the Bugs followed us.
"Well," I said, "we're heading toward a portal at generally the right angle. Carl, you're going to have to take the lead sooner or later. We'll need your instruments to shoot the hole."
"Right. Want me to do it now?"
"If you want… Hey!"
A blinding white fireball erupted from the surface ahead and a few degrees to the right. Sam turned sharply, dodging its expanding edge and bringing us back to our original heading. There was no concussion and the explosion had caused us no damage so far as we could tell.
"That was a warning shot across our bow, I suppose," Sam said.
"They are herding us," I said angrily. "Rats."
"Let me get off a salvo of balloons at 'em," Carl suggested eagerly.
"No, Carl. Too many of them, and they're wise now. You say you don't have any offensive weapons at all?"
"I do, but l have to be under attack directly for them to work… which I guess makes 'em defensive, actually. The Tasmanian Devils are offensive, that I know. Trouble is, I only got two left."
"Save 'em," I said. "Are you running out of Green Balloons?"
"No, I can generate an indefinite number of those."
"Are you sure about that?"
"Pretty sure."
"Okay. Let's continue on this course until we figure out what to do next."
Ten minutes and no ideas later, something appeared up ahead.
At first it was a thin dark line which grew to become a long notch set into the surface, deepening toward its farther end. We were headed straight for the beginning of the gradually narrowing ramp that descended into it. I could guess where it led.
"Let's try to turn off again," Carl said.
"No time," Sam said.
And there wasn't. With no visual cues outside there had been little sensation of speed, but a quick check of the instruments told me that Sam was roaring along at a terrific clip. In very short order we entered the mouth of the ramp. Sam braked as we descended. We could see the end of the notch now, a sheer wall into which was set a hemispherical opening.
A tunnel.
"Wonder how much to park down here," Sam said. "Have any spare change?"
"Where's the guy who hands out the tickets?" I asked.
"I hope we can get out of here," Carl said worriedly.
"There's got to be a way out," I said. "Actually, this may be a good thing. The Green Balloons will be more effective underground. No way to duck 'em."
"I guess we really don't have a choice."
"Couldn't take a chance that they'd stomp us. They could have. Obviously they're curious―maybe they want to talk."
The tunnel was large, its walls glowing with the same spooky blue light that dimly lit the surface. The passage continued straight for about half a kilometer, still gently descending, then went into a wide banked turn to the right.
"Carl,"
"Yeah?"
"Fire a balloon back up the tunnel."
"Will do."
He did. A greenish light came from behind, then faded.
"That should slow 'em down, if they follow," I said. "Shoot a few more for insurance."
"Roger."
The turn became an interminably descending spiral. The turning radius was enough to preclude dizziness, but at about the twelfth circuit I began to get a little disoriented. I thumbed the toggle that gave me back manual control of the rig and slowed down. We descended still farther, about ten more levels, until the tunnel straightened out, ran along for a few hundred meters, then debouched into a huge circular cavern. Spaced evenly along the walls were entrances to passageways radiating outward. I swung the rig sharply to the left and aimed for a tunnel-mouth that took my fancy.
For the next half-hour we wandered aimlessly through a maze of gigantic rooms connected by ramps and passageways. Here and there we passed huge empty bays cut into the walls going back at least a hundred meters. There was nothing at all in them, no equipment or machinery. After finding at least a dozen of them, something occurred to me.
"Everyone on auxiliary motors," I ordered.
"Good time to test ours under field conditions," Sean said, referring to the strange new backup engine which Ahgirr technicians had retrofitted Ariadne with. From what I had gathered, it was a thermoelectric motor powered by the controlled burning of oxidized fuel pellets―sort of like a solid-propellant rocket running in slow motion. I didn't entirely understand how it worked, but Sean reported good numbers on his readouts. It was working, more or less. (Ahgirr technology was odd in that it was highly advanced in some areas, like electronics, and clumsily jury-rigged in others.)
"Good thinking, Jake," Carl said. "Neutrinos can travel through solid rock like it wasn't there."
"Should have thought of it earlier."