Anna nodded her agreement and squeezed his arm. They were both so excited, I wondered if I were the irrational one. The more enthusiastic they became, the more uneasy I felt. No sharks and tigers, maybe — but wouldn’t there still be natural selection, even if it went on very slowly?

Shades of Malthusian Doctrine: the number of organisms would follow an increasing geometric progression, and the food resources were finite. Eventually there would have to be a balance, a steady state where dying organisms were just replaced by new ones; and then natural selection ought to take over, with competition between different forms. I didn’t have that logic explicitly in mind, all I knew was that something seemed wrong. And I knew that Mac was no biologist. I stared at the screen and shook my head.

“So what happened to Lanhoff and his crew?” I said.

There was a long, uneasy silence.

“Quite right, Jeanie,” said McAndrew at last. “We still have no answer to that. But we’re going to find one. Will can stay here, and Anna and I will go down there now.”

“No.” My pulse began to race. “I won’t allow it. It’s too dangerous.”

“We don’t agree,” said Anna softly. “You heard McAndrew, he says we should look down there — and we’ll go in our suits, so we’ll be well protected.”

Fools rush in where angels fear to tread. Anna Griss knew how to survive in an Earthbound bureaucratic free-for-all, but she was a long way from her home ground. And if she was relying on Mac’s instincts to save their skins…

“No.” My voice cracked. “Didn’t you hear me? I absolutely forbid it. That’s an order.”

“Is it?” Anna didn’t raise her voice. “But you see, we’re not in the spacecraft rendezvous mode now, Captain Roker. The Star Harvester is tethered to the planetoid. That means I command here, not you.” She turned to McAndrew. “Come on, let’s make sure we’re fully prepared. We don’t want to take any risks.”

Before I could speak again she reached forward to the monitor. I suddenly found that I was looking into a blank screen.

It took me a long five minutes to patch in a substitute communications link between the computers of the Hoatzin and the Star Harvester.

When the auxiliary screen came alive I saw Will Bayes fiddling with the control bank.

“Where are they, Will?”

He turned quickly. “They’re on the way down to the surface. Jeanie, I couldn’t stop them. I said they shouldn’t go, but Anna wouldn’t take any notice of me. And she has Mac convinced, too.”

I knew McAndrew — he hadn’t taken any convincing at all. Show him an interesting intellectual problem, and preservation of life and limb came a poor second to curiosity.

“Don’t worry about that, Will. Link me to the computer on board the transfer pod.”

“What are you going to do?”

“Go after them. Maybe Mac is right, and they’ll be fine, and in no danger. But I want to be the rearguard and trail along behind them, just in case.”

Will could have probably flown the pod to pick me up in an emergency, and I knew that the computer could have done it with a single rendezvous command from me. But Will and the computer would have followed the book on permissible rates of acceleration and docking distances. I took remote control of the pod myself, overrode the computer, broke every rule in the manual, and had the pod docked at the Hoatzin in less than fifteen minutes. Going back to the Star Harvester we beat that time by a hundred seconds.

Will was waiting at the main lock with his suit on. “Something has gone wrong,” he said. “They told me they would send a signal every ten minutes, but it’s been over twenty since the last one. I was going to go down and see what’s happening.”

“Did you see any weapons on board when you were looking over the ship earlier?”

“Weapons?” Will frowned. “No. Lanhoff had no reason to carry anything like that. Wait a minute, though, what about a construction laser? That can be pretty dangerous, and there are plenty of those in Section Six.”

“Get one.” I was preparing the transfer pod for a rapid departure from Star Harvester if we needed it. One time in a thousand, a precaution like that pays off.

“I’ll get two.”

Will was off along the tube between the Sections before I could argue with him. I didn’t want him with me in the middle of Manna — I wanted him available to help me out if I ran into trouble myself.

What was I expecting? I had no idea, but I felt a lot better when I had my suit firmly closed and a portable construction laser tucked under one arm. Will and I went together to the entrance of the long tunnel that led down to the interior of Manna.

“Right. No farther for you.” I looked at the peculiar way he was holding the laser, and wondered what would happen if he had to use it. “You stay here, at the head of the shaft. I’ll send you a signal every ten minutes.”

“That’s what Anna said.” His words echoed after me as I dropped away down the broad shaft.

The illumination came only from the light on my suit. Seen from the inside, the shaft out of the cargo hold dropped away in front of me like a dark, endless tunnel. Manna’s gravity was negligible, so there were none of the Earth dangers of an accelerated fall. But I had to take care to remain clear of the side of the tunnel — it narrowed as we went deeper into the planetoid’s crust. I drifted out to the center of the shaft, turned on the coupling between the suit’s conducting circuits and the pulsed field in the tunnel wall, and made a swift, noiseless descent.

The three kilometer downward swoop took less than a minute. All the way to the airlock at the bottom I watched carefully for any sign that McAndrew and Anna had met trouble there. Everything was normal.

The drilling mechanism at the end of the shaft was still in position. Normally the shaft could extend itself through hard, frozen ice at a hundred feet an hour. When they came to the liquid interior, however, Lanhoff had arrested the progress of the drill and installed the airlock. It was a cylindrical double chamber about six meters across, with a movable metal wall separating the two halves.

I cycled through the first part of the lock, closed the wall, and went forward to the second barrier. I hesitated in front of it. The wall was damp with a viscous fluid. The airlock had been used recently. Anna and McAndrew had passed through here to the liquid core of the planetoid. If I wished to find them I must do the same.

Was there a port? I wanted to take a good look at the interior of Manna before I was willing even to consider going through into it.

The only transparent area was a tiny section a few inches across, where a small panel had been removed and replaced by a thin sheet of clear plastic. Lanhoff must have arranged it this way, to make an observation point before he would risk a venture beyond the lock. Despite his curiosity referred to by Anna, it suggested that he was a cautious man — and it seemed to increase the odds against me. I was diving blind, and in a hurry.

I drifted across and put the faceplate of my suit flat against the transparent plate. The only illumination in the interior was coming from my suit, and because it had to shine through the port I was confused by back-scattered light. I held my hand to shield my eyes, and peered in.

My first impression was of a snowstorm. Great drifting white flakes swam lazily across the field of view. As I adjusted to the odd lighting, the objects resolved themselves to white, feathery snowballs, ranging in size from a grape to a closed fist. The outer parts were in constant vibration, providing a soft-edged, uncertain shimmer as they moved through the pale yellow fluid of Manna’s interior.