Watching him cheerfully sipping sparklewater and idly skimming the sports page, my contempt began to be tinged with pity.

"We've got lots to do today," I said. "You've got two appointments, one with the Countess Krak and the other with Doctor Crobe."

"Hey, look at this!" and his nose was buried in the sports page. "Timbo-chok just beat Laugher Girl in a five lap free-for-all at Mombo Track! Well, well! That Laugher Girl was the fastest car at Mombo. Who'd have thought it possible? Let's see, here, who was driving . . . ?"

The interior of ancient Spiteos is a labyrinth of windowless, black stone. Above ground level it is mainly a deserted hulk but huge with rooms and vaults and tunnelled passageways. The original inhabitants of the planet believed in fortress security – but it had availed them not at all when our forefathers came.

When we left the room, we were already pressed for time. I had to make a stop at the armory – to get a dummy-loaded, dud blastick to secretly exchange for the one he was now carrying. And Countess Krak was notorious for not wanting to be kept waiting: her reaction to anyone being late could be deadly.

Accordingly, I was not pleased at all when Jettero Heller insisted on walking. I supposed he wanted the exercise – athletes are a trifle loony on the subject – and, obedient to my orders not to arouse his suspicions, I had to acquiesce. So we avoided the first stage of tubes and began a wandering course through the upper reaches of Spiteos, a badly lit stroll through endless mazes of dust.

He was wearing the hull boots. Now, these boots have peculiar soles: they alternate bars of powerful magnets with ridges of a coarse fiber. To walk on a metal wall or deck, the magnet bars are left down – and they are very handy in weightless space and could undoubtedly save your life. But when walking on stone or nonmagnetic surfaces, one simply clicks one's heels together in a certain way and the magnets draw up, leaving one walking on the rough fiber ridges.

But Jettero Heller was walking on stone floors and steps and he had left the magnets down!Clickety-clack, clatter, clatter! Loud! He sounded like a tank!

It got on my nerves. All he had to do was click his heels and the magnets would draw up and leave him walking silently.

In espionage one has to cultivate a soft tread. A good agent practices and prides himself on being able to walk with total silence on anything, even gravel. The success of a mission – yes, and even his life – may depend on how silently he can move about.

Heller was not only walking with the subtlety of a tank column, but every ten or fifteen paces he would do a little extra skip, a real loud snap of metal on stone. Deafening!

He seemed much interested in the walls themselves and now and then would rap them with a ring he wore. "These ancients sure could build," he commented many times.

So clickety-clack, clank, we toured the long passages, wandered through huge, deserted halls and banged our way down filthy steps.

The dust was irritating to my nose and I sneezed repeatedly. I was getting a little tired – I am not one to do much exercising. "Look," I said, "we're going to be late and the Countess is going to rip our heads off. Surely you've had enough exercise for the day."

"Oh, I'm sorry," he said. "It's all just so interesting. Did you know these ancients had no metal tools? Nobody knows how they fashioned these chambers or even how they got rid of the rubble. We couldn't do it today unless we used disintegrators. Do you realize there are no seams? No joints. All just hollowed out with no decent tools." He clatter-clanked on for a while. "I wonder why the Voltarians thought they had to wipe those ancients out. They couldn't have been much of a menace." Oh, I thought, you and Lombar will never get along. Unless one wipes out the riffraff and excess baggage, one gets an awful lot of problems – problems like we have now. If we let every conquered people live, we would have even more trouble than we've got. Yes, I could imagine an argument between Lombar and Heller. It would end in a dead Heller! I'd better keep them separated if I was ever to get this Heller to Blito-P3!

Praise the Gods, we finally got to the armory. Heller walked on down the passage a ways, examining walls. I stepped up to the armory counterdoor and matched my identoplate to the lock. It swung open.

The old cretin that was custodian of the place came hobbling up to the counter, scowling and hostile. We don't get along. "What are you bothering me for today?" he rasped.

In the Apparatus we have a sign language we do when there's a chance of being overheard. Giving the armory clerk some nonsense cover talk, and with my back to Heller, I signalled for an 800-kilovolt blastick, specifying a dummy load. It was not much trouble for the old cretin – they ship blasticks with a dud cartridge in the chamber to protect the firing electrodes – but you'd thought I was asking for a battleship, the way he frowned and snarled. All he had to do was walk ten feet to a shelf and pick one off it, open it to be sure it had a dummy cartridge in it, hand it over and push my identoplate on the receipt. He did and slammed the upper door in my face. I had also wanted a stungun but his action seemed too final.

Heller was feeling the wall from high up to floor level. "Aha!" he said. "Ground level." It was my opening. I was about to do something that, had he been trained in espionage, he would have been alert to.

"How do you know?" I challenged.

"Half a degree," he said. "Temperature difference. The outside ground is right about here, just below waist level."

"Half a degree?" I scoffed. "Nobody can tell half a degree of temperature with his hand."

"Can't you?" he said, seeming much surprised. "The outside, at this time of day, is in sunlight; these walls are about three feet thick at this level. But the conduction of heat up here," and he reached way up, "is half a degree above floor level." I knew he would do it, the fool. He reached for my hand and made me pat the wall up high and then put my palm against a point close to the floor. "It's a matter of training," he said.

Yes, a matter of training. Naturally, I was overbalanced by the way he moved my hand; I stumbled against him. Using my other hand with an expert smoothness, all in a split second, I eased his blastick out of his boot top, shook the dud duplicate out of my sleeve and into the boot. I straightened up and, in doing so, put the live blastick in my breast pocket. He was now "armed" with a dud weapon. The pickpockets of the Apparatus are excellent teachers.

"I couldn't tell the difference," I said, "but then you're the expert at such things. Come along, we're late. The Countess will be furious!"

"All right," he said. "But just a moment. Let me finish this." I had no idea of what he was talking about. He put out his foot and for a moment of heart failure I thought he had detected the weapons switch. But no. He gave the floor a single hard kick. The magnet bars went CLANK! Then he clicked his heels together in the action that makes the metal draw up above the fiber ridges. Praise the Gods, that would be the end of all his clanking.

But we didn't move on. With a gesture that further detained me, he drew out a large sheet of paper and one of those constant-flow engineer pens. He put the paper on a smooth wall spot and began to draw.

His hand was moving so fast it was just a blur. I had never seen an engineer doing a field sketch before; I realized why their pens had to flow such volume. But I was too impatient to be very impressed.

In a few moments, he flipped the paper at me and put the pen away.

I was looking at a complete, fully measured sketch of the above-ground interior of Spiteos! The distances, floor heights and now, even the ground level were marked in! And it was all beautifully done, almost as good as you get from a draftsman after a week of work.