Bayes blinked. “You seem to know all about this already. Did Anna already brief you? Lanhoff’s work is all supposed to be a big secret.”

I had some sympathy with him. Briefing McAndrew is an unrewarding experience. At the end he seems to know everything you know and be able to explain it and apply it better. Now Mac was shaking his head and looking puzzled.

“She didn’t mention any of this to us. But I knew most of it years ago. Not the particular place in the Halo where we might find complex organic materials, but at least the fact that they might be there. It’s not a new theory at all. Hoyle suggested it more than a hundred years ago. I just don’t understand why there’s anything secret about it. A finding like this one ought to be available to anyone.”

“There’s a reason. Wait until you know Anna Griss a bit better and you’ll understand.” Bayes was looking outside for his first glimpse of the Hoatzin, which was now only a couple of hundred kilometers away. “She’s the hardest worker I know, but she’s super-ambitious. She wants to run the whole Council someday — tomorrow, if she had her way. When Lanhoff came to her with his proposal, the first thing she did was hit it with a classified label.”

“Didn’t anyone argue with her?” I said.

“No. Try it. It’s not something you’ll do more than once. There were a few mutterings, that was all. Anna offered some positive incentives, too. She thinks this will make her famous, and push everybody in the Department ten rungs up the management ladder.”

“Just because we’ve got a bit more information about the composition of the Halo? Not much chance of that.” McAndrew snorted his disbelief.

“No.” Bayes was still peering out of the port. “Lanhoff persuaded her that he had the only answer to the System food problem. All he needed was money and a ship, and USF permission to make some orbit changes to a few bodies out in the Halo. Good God!” He turned back from the scope. “There’s the oddest-looking ship out there. Surely we’re not proposing to chase after Lanhoff in that thing?”

Lanhoff’s suggestion sounded reasonable until you sat down to think about it. Out in the Halo, off where the Sun was nothing more than an extra-bright star, mountains of matter drift through space, moving to the tug of a faint gravitational current. Most of them are frozen or rocky fragments, water ice and ammonia ice bonding metals and silicates. But swarms of them, in a toroidal region three hundred billion miles from Earth, are made of more complex organic molecules. If Lanhoff were correct, we would find an endless supply of useful compounds there — all the prebiotic materials from which foodstuffs are easily made. They needed only warmth and a supply of the right enzymes to serve as catalytic agents. Cellulose, polypeptides, carotenoids, and porphyrins could be transformed to sugars, starches, proteins, and edible fats. The food supply of the whole solar system would be assured for a million years.

Now sit down and think about it again. How do you seed a hundred million worlds and turn them to giant candymountains, when the nearest of them is so far away. How do you heat them; how do you get them back where they will be useable?

If you are Arne Lanhoff, none of those questions will deter you. The enzymes you need are available in small amounts in the inner system; once a body has been seeded and heat is available from a fusion reactor, enzyme production can proceed at an explosive pace. It will suffice to begin with just a few hundred thousand tons of the right enzymes, and make the rest where the supply of raw materials is assured. The types of enzymes needed to split polymer chains are well known, but the only sort of ship that can carry this much load is a boost-and-coast vessel with a maximum short-duration acceleration of only two-tenths of a gee. So be it. Plan on a trip out to the Halo that will take a couple of years, and allow another year or two to trundle around from one cometary body to the next, seeding and performing necessary orbital adjustments. The continuous-thrust engines that will be attached to each body add another two million tons to the ship’s initial payload. So be it. Fusion heaters to warm the frozen interiors will add a million more. Don’t worry about it. For a project of this size and importance, the Food and Energy Council will find the money and equipment.

McAndrew had shaken his head when Will Bayes described the plan to place the seeded bodies into radial orbits, thrusting in toward the Sun. “Man, do you realize what it will take to stop one of them? We’ll be trying to catch a billion tons travelling at two thousand kilometers a second.”

“Arne Lanhoff knew that before he left. He was planning just enough drive to bring them to the Inner System in twenty years. By that time they’ll be warmed and transformed in content.” Bayes smiled contentedly. “He felt sure that you’d find ways to catch them and slow them. It’s the sort of thing your group finds challenging.”

“Challenging! He’s insane.” But two minutes later McAndrew was miles away, working on his new puzzle. Arne Lanhoff knew his man rather well.

The ship that had left the Inner System four years ago did so with no fanfares or publicity. The Star Harvester was a massive set of linked cargo spheres with electromagnetic coupling. Each Section had an independent drive unit powered by its own kernel. It was quite similar to the Assembly that I pilot on the Earth-Titan run, and I was glad to know that I’d have no trouble handling it if the need arose.

That need might well arise. The Food Department had received regular communications from the Star Harvester crew during the long trip out — two years Earth-time, and the ship was too slow to make it noticeably shorter in shipboard time. Lanhoff had finally reached his first suitable target, a fifteen-kilometer chunk of ice and organics. He had officially named the body Cornucopia, planted the enzyme package, the fusion furnace, and the drive, and then started it on the long drop in towards the Sun. Without the drive it would fall for millennia. With a little continuous-thrust assistance Cornucopia would be crossing the orbit of Jupiter sixteen years from now. By that time it would be a fertile mass of the raw materials of nutrition, enough to feed the entire solar system for five years.

“No problems. Complete success in all phases,” read Arne Lanhoff’s message as they moved on to the next selected target, a mere five hundred million miles away.

The mission had operated perfectly for another five targets — each one named, processed, and directed toward the Inner System. Ambrosia; Harvest Festival; Persephone; Food of the Gods; and Demeter.

Then the pattern was broken. The seventh target had been reached ninety days ago. After an initial message announcing contact with the body Manna, a huge organic fragment sixty kilometers in length and incredibly rich in complex compounds, Star Harvester became inexplicably silent. A query beamed to it from Triton Station fled off on its nineteen-day journey, and an automatic signal of message receipt finally returned. But no message originated in the ship’s transmission equipment. Arne Lanhoff and his crew of four had vanished into the void, three hundred billion miles from home.

Our troubles didn’t wait until we were out in the Halo. As soon as Anna Lisa Griss arrived on board the Hoatzin, only six hours before our scheduled departure time, we had a problem. She looked around the living quarters disbelievingly.

“You mean we’re supposed to stay in this little space — all of us? It can’t be more than three meters across.”