The testing proceeds. The rusty voice spoke again. It comes close to completion… close enough to be sure that the modified one is a true human, and acceptable. It is not necessary for you to be here…

“Then take us back to the surface,” Rebka said.

“No!” Darya moved in front of him. “Hans, if we go back now we may as well never have come here at all. There are so many things we might be able to find out here about the Builders. We may never have as good an opportunity.”

You seek the Builders, the creaking voice went on, as though neither human had spoken. I am not a Builder, and I cannot guarantee the result. But if it is your desire to encounter the Builders—

“It is!”

Then, GO.

“No. Darya, will you for God’s sake wait a minute! We don’t know—”

Rebka’s shout was too late. They were standing on the brink of the tunnel as the edge turned suddenly to vapor.

Free-fall!

Rebka looked down to his feet. They were accelerating at a couple of gees along a featureless vertical shaft that ended half a kilometer below them in a darkness so total that the eye rejected its existence.

“What is it?” Rebka heard Darya’s despairing cry beside him.

“It’s Glister’s gravity field — whatever creates it — maybe a…” He did not finish the phrase. If they were falling toward the event horizon of a black hole they would know about it soon enough — know it for maybe a millisecond, before tidal differential forces reduced their bodies to component elementary particles.

“Hans!” Darya screamed.

Two hundred meters to go, still accelerating, faster than ever. Maybe a second left. And now the darkness possessed a structure, like a roiling whirlpool of black oil, curling and tumbling onto itself. They were heading into the churning heart of that dark vortex.

Rebka’s empty stomach was churning, too.

A fraction of a second to go.

Childhood on Teufel had taught him one thing above all others: there was always a way out of every fix — if you were smart enough.

You just had to think.

Think.

Apparently he was not smart enough. He was still thinking, unproductively, as he dropped into the depths of that writhing blackness.

The unmanned Summer Dreamboat had arrived in one piece and in working order.

That was the good news. The bad news was that it had been touch and go.

Five grazing encounters with Phages had delivered hammer blows to the Dreamboat’s hull, one strong enough to dent and puncture the top of the cabin. The repair was not difficult, and Birdie Kelly was already half finished. But the significance of those five near misses was not the damage that they had done. It was what they revealed about the state of the Phages. Steven Graves and E. C. Tally had monitored the ascent of the Dreamboat and were agreed for once: the little ship’s survival, even with all collision-avoidance systems active, had been mainly a matter of luck. The Phages were more active than ever, all the way down to the surface of Glister. A descent with accelerations that humans could stand had less than a one-percent chance of success.

The Summer Dreamboat had been moved for repairs into the capacious ore hold of the Incomparable. Graves and Tally were floating free in the air-filled interior, talking and talking.

And watching me work, Birdie thought. Same as usual. The other two were long on talk, but when anything calling for physical effort came along they managed to leave all the doing to him. And they lacked a decent sense of danger. Birdie hated to work with heroes. He had listened to Steven and E. C. Tally casually talk odds of a hundred to one against, and shuddered. Fortunately, Julius Graves seemed to have more rational views.

“Those odds are totally unacceptable,” he was saying. “When you and Steven are in agreement, I am forced to listen. We cannot afford to take such a risk.”

“May I speak?”

“Which means we have a real problem,” Graves continued, ignoring Tally’s request. “J’merlia is on Dreyfus-27. Probably deep inside it, since he does not answer our calls. So he can’t help. And everyone else is on Glister. And we have no safe way of getting to them.” He paused. “Did you say something, E.C.?”

“Steven and I agreed on the probability of survival if the Summer Dreamboat simply makes a direct descent to Glister. Or rather, we disagreed in the third significant digit of the calculated result. But there are other options. It depends on the probability level which one uses to define ‘safe.’ For example, there is a technique that would raise the probability of a successful landing of the Summer Dreamboat on the surface of Glister to a value in excess of zero-point-eight-four.”

“A five-out-of-six chance of getting there in one piece?” Julius Graves glared at Tally. “Why didn’t you mention it earlier?”

“For three reasons. First, it came to me only after a review of analogous situations, of other places and times. That review was completed only thirty seconds ago. Second, the technique should provide a safe landing, but the odds of a safe subsequent ascent are incalculable without additional data concerning the surface of Glister. And third, the procedure would probably lead to the loss of a valuable asset: the Incomparable.”

“Commissioner Kelly.” Graves turned to Birdie. “The Incomparable is the property of the government of Dobelle. As the representative of the government, how would you view its possible loss?”

Birdie had finished the patch on the Dreamboat’s hull and burned his thumb doing it. He pushed himself off and glared around the Incomparable’s hold as he floated up to grab a support beam at Tally’s side.

“It’s a filthy barrel of rust and rot, it stinks like a dead ponker, and it should have been thrown on the scrap heap fifty years ago. If I never see it again, that’s too soon.”

Tally was frowning at him. “Am I to take it, then, that you would sanction the potential loss of the Incomparable?”

“In one word, matey, yes.”

“Then if I may speak, I will outline the technique. It is something that can be found in the older parts of the data banks. In old times, when human individuals wished to accomplish an objective that certain other guarding entities sought to prevent, they often employed a method known as creating a diversion…”

Agreement in principle did not guarantee agreement in practice. E. C. Tally and Steven Graves had argued endlessly about the best method. Should the Incomparable be sent in well ahead of the Dreamboat, passing through the periphery of the cloud of orbiting Phages and seeking to draw them away from Glister? Or was it better to fly the old ore freighter on a trajectory that would impact Glister, and take the Dreamboat in not far behind, relying on its being ignored in the presence of the freighter’s larger and more tempting target?

Tally and Steven Graves had finally agreed on one thing — that they had insufficient data.

“Since there is not enough information to make a reasoned choice,” Tally said apologetically to Birdie Kelly, “the only thing I can suggest is that we resort to aleatoric procedure.”

“What’s ‘aleatoric’ mean, when it’s at home?” Birdie was reaching into his jacket pocket.

“An aleatoric procedure is one that contains chance and random elements.”

“Why, that’s just the way I was thinking myself.” Birdie produced a deck of cards and shuffled it expertly. He held it out to Tally. “Pick a card, E.C., any card. Red, and the ships fly a long way apart from each other. Black, and we tuck ourselves up the old Incomparable’s tailpipe.”

Tally selected a card from the spread and turned it over. “It is black.” He had stared in great curiosity when Birdie shuffled the deck. “What you did just then — it was difficult to see, but is it designed to randomize the sequence?”