his face. 'Dearie me, I think I've made a boo-boo.'
'What are you saying?' I managed to get out.
'Um… I think I'd better take you back to Emerald City. Right now. Follow me.'
We followed him. Another sphincter-valve, this one much smaller than the first, was set into the far wall. It opened to admit us, and we went through into a curving tube-shaped corridor that bent to the right and led into a circular room. In the center was a high cylindrical platform on which rested a wedge-shaped box affair looking somewhat like a lectern. Arthur stood in front of it and began to slide his fingers across the box's slanted top face. A control panel, I thought.
Nothing much happened. I didn't feel any movement. I looked over Arthur's shoulder. The triangular panel, made of the same dark material that the rest of the ship was composed of, was totally blank, yet Arthur seemed to know where to put his fingers.
'Want a view?' Arthur asked.
'Huh? Oh, yeah.'
The ship around us disappeared.
Darla squealed, and Lori fell to all fours. Carl jumped back, yelling, 'Jesus Christ!' He stared unbelieving at his feet, beneath which was nothing but air.
I stared down, stamping my right foot. The floor was still there-something was there, anyway. I turned around. And behind us, about ten meters away, flying along with us like a escorting fighter, was the truck.
We were soaring in open air about three hundred meters above the surface of Microcosmos. Arthur still had his hands extended over the now invisible control panel.
'Sorry,' he said. 'I should have warned you. Let me opaque the ship's mass a little.'
The walls and floor came back abruptly, then gradually faded to full transparency, but this time they looked like tinted glass.
'Do you have a sense of the ship around you now?' Arthur inquired.
'Yeah, better,' I said.
Lori got up. 'I'm going crazy,' she declared. 'I really think I'm gonna go completely bats.'
'Hang on, honey,' Darla said soothingly, putting an arm around her shoulders.
'Where did you get this… ship?', I asked.
'Belongs to Emerald City's fleet,' Arthur told me. 'It's a spacetime ship. Goes anywhere, anytime. Zips you there real fast.'
'Yeah?'
'Yeah. It's probably the most advanced spacecraft ever built. Don't ask me who built it. I'd break my jaw trying to pronounce the name.'
'Do you know how it works? What drives it?'
'Oh, quantum this, that, and the other thing. You really want me to go into it? You couldn't understand it, anyway.'
'Forget it.'
The patchwork quilt of Microcosmos rolled beneath us. Our airspeed couldn't have been much. Ahead, I could see the Emerald City atop its citadel, sparkling in the light of the setting sun.
'You have to take it easy going short distances,' Arthur went on, anticipating my next question. 'You can't do continuum jumps near big masses. I mean, you can do them, but it's tricky. Even for me. And I'm pretty good at driving this thing.'
'You do a lot of flying?'
'Never. This is my first time.'
'I see.' I shrugged to myself.
The ship made its approach to Emerald City. Everything seemed to be going fine until we suddenly veered off. The world below us tilted crazily.
'What's wrong, Arthur?' I said, fighting an attack of vertigo.
'Something's coming our way.'
I searched the sky and found it. It was a yellow glowing ball trailing streamers of fire, streaking down at us.
'What the hell is that?' I shouted.
'I don't know,' Arthur said calmly. 'Some kind of weapon. Don't worry.'
'Worry? Who, me?'
The ship made a dizzying turn and headed away from the green castle. The fireball executed the same maneuver and streaked after us, hot on our tail. Our speed increased rapidly, but there was no feeling of acceleration, no G-forces. We climbed swiftly, then leveled off. The fireball did the same, and it seemed to be gaining. Arthur appeared to be aware of this without having looked.
'Uh-oh,' he said. 'Hang on, kids.'
Arthur proceeded to put the ship through some impossible maneuvers. We flipped, looped, dived, pulled up, then went into what would have been called a stall, had it been done by an airplane. Then we dropped like a stone, tumbling end over end.
I fought off vertigo, closing my eyes. There was absolutely no physical sensation of movement.
When I opened them again, we were flying close to the ground at tremendous speed. Behind us, the fireball was pulling out of a dive to match our altitude.
'Dearie me,' Arthur fretted. 'I can't seem to shake this thing off our tail.'
'Doesn't this ship have any weapons?' I asked.
'Not much offensively, but a whole bunch defensively. The ship's supposed to be invulnerable to just about any weapon ever created. Anyway, that's how it was touted in its day. But I can't take any chances. I have no idea of what technological culture that fireball may have come out of. It might have been specifically invented to challenge this ship's claims to invulnerability. You know how arms races go.'
We shot up into the sky again and did a series of evasive maneuvers, these more improbable than the last. The fireball matched our every move.
'Dearie me!' Arthur exclaimed. 'Now I'm starting to worry…'
'What about those defensive weapons?'
'I've already tried to neutralize it. Nothing worked.'
'Can't you shoot it down?'
'Dogfight with it?' Arthur cringed. 'You don't know what you're saying. Dogfighting is probably that thing's trump suit. You never know what to expect with these standing-wave energy weapons, which is probably what it is. It might be able to absorb the energy of an attack and grow even more powerful.'
I looked ahead. The edge of the disk-planet was coming up fast.
'We're running out of world, Arthur,' I said, trying to sound as composed as possible.
'That may be our only chance,' he replied.
Our speed must have been stupendous by then. The edge of Microcosmos swept past, and we streaked out into space. The planet shrank behind us, its disk tilting away, bringing the edge into view. Forty-five degrees along the rim of the world, the luminous sun-disk was falling below the horizon. Beneath us, the world-edge was rounded and looked metallic, busy with embossed geometric patterns which could have been mazes of pipelines, conduits, power stations, and other technological facilities. I estimated the edge's thickness to be about two hundred kilometers. There very well could have been roads down there, but I couldn't make any out.
The other face of the planet, still dark, flipped up toward us. Before long, though, the sun, now on the opposite side, peeked back over the horizon and sent long shadows across the land. It was magnificent to watch, even under the circumstances.
The fireball had dropped back. Suddenly, there was a split second of a blinding flash. The walls opaqued instantly, cutting it off. Purple spots swam in front of my eyes.
'Well, we outran it,' Arthur said, breathing a sigh. 'It was losing energy, so it gave up and dissipated. Rather spectacularly, wouldn't you say?'
'Anything else coming at us?' I asked.
'No.'
'Any idea who sent it?'
