With vigorous kicks he set off in what he hoped was the right direction.

How would he know when he had gone far enough? Each of us has an inborn sense of time, and Richard Blade had developed his, learned to depend on it. If the time-sense failed, there were his lungs. His lungs would tell him when he could go no further.

There was a vague saltiness in the water.

He paid little attention to that, only to the cold.

The cold!

He had not realized that it would be so numbingly, horribly cold. Fragmentary pictures flashed through his mind. Penguin Club swimmers diving through holes cut in the ice. How long did they stay in the water? Nazi experiments with cold during World War II. How long did the victims survive? These were things Richard suddenly wished he had studied more carefully, wished he had added to his vast store of trivia.

His sense of time said, «One minute.» He unbuckled his weighted belt and let it drop, then drifted, not moving a muscle, letting his natural buoyancy lift him slowly, all too slowly, toward the surface.

His head broke water!

He rolled onto his back and inhaled joyfully once, twice, three times, while he took his bearings.

Yes, he was near the Tower embankment.

Yes, he was sheltered by that embankment from the view from the probable location of the guards.

Thank God, he thought, and went on breathing.

In the distance he could see his boat, almost invisible in the darkness and fog. The current would soon take it far downriver. He turned onto his belly, breathing more normally, and treaded water. He too was drifting, drifting beyond the place where he'd hoped to land. He thrust his feet downward.

As he'd expected, there was sand down there.

Smiling, though he was shivering uncontrollably, he waded against the current.

There, exactly where he'd expected it, was the Queen's Stair leading up out of the water. He sat on a step, just above the water level, and removed his flippers and mask. He would need them no longer. He lowered them noiselessly into the black water and let them go.

When he felt he had fully recovered his wind, he started up the stairs. At the top, he knew, he would be exposed, but not for long.

At the head of the stairs he crouched, waiting for the fog to thicken, listening for the guards. There was nothing to be heard but the usual murmuring roar of the city and an occasional auto horn. He raised his head and peered around.

The fog closed in.

He sprang up and ran, clutching his tranquilizer pistol so it wouldn't bang on his thigh. He glimpsed a few leafless trees, an ancient cannon pointed riverward, then he was over the rail and into the filled-in moat. Keeping low, he padded toward St. Thomas's Tower, where he vaulted another fence and found himself in the broad archway of the Traitor's Gate, leaning against the massive grillwork.

He listened.

Nothing.

He looked around.

Nothing but slow-moving mist.

He located the heavy combination padlock at the center of the gate, dangling from a length of chain. Richard knew the ways of padlocks! He set to work.

One tumbler. Two.

It was easy, particularly since, having once seen the lock opened, he had a fair idea of the combination already.

The lock released on the first try.

He opened the ponderous gate, and it creaked. Had anyone heard? Apparently not. He slipped inside and resecured the chain, relocked the padlock.

In the yellow light from a single bare bulb in the ceiling, he crossed the inner chamber and located the secret door. It opened easily.

He passed through and trotted along the dim damp tunnel beyond, through the maze of subbasements, on to the familiar elevator door.

Would his thumbprint still be stored in the computer's memory banks? Why not? Everyone thought he was on the other side of the planet. Why would they bother to change the banks?

He pressed, the elevator button firmly, letting the button read his print; wondering what he would do if the computer rejected him.

With a swish the elevator arrived and opened.

Richard stepped inside. The door slid shut.

As the elevator plunged downward, he opened the mouth of his pillowcase bag, wondering, Will there be someone on duty at the entrance to the complex, next to the elevator door? Sometimes there was and sometimes there wasn't. Special Services had become rather lax in the placement of its human guards for years now, putting too much confidence in supersophisticated electronic devices. Richard had warned them about that, but nobody had listened. Now he would give them a demonstration.

The elevator slowed to a stop. The heavy bronze door rolled open.

There was someone on duty, sitting at the olive drab desk in the brightly-lit foyer, reading a magazine, a lean fellow in green coveralls. As he looked up, surprised, Richard recognized him as Bill Jemison, one of Lord Leighton's techmen.

«Hello, Bill,» Richard said casually, stepping from the elevator into the welcome warmth of the underground installation. The door closed behind him.

«Well, if it isn't Richard Blade,» Jemison answered. «I didn't know you were back from the states.»

«Leighton called me back for a mission.» Richard noted that there was an intercom unit on Jemison's desk. It would not do for Jemison to punch a button on that unit and give the alarm.

«I see you're already greased up,» said Jemison.

«That's right.»

«I'm glad to see you looking so well. I heard the last trip was a rough one. Ferguson told me you might be hospitalized for a long while.»

Good old Ferguson, Richard thought with irony. He said, «It wasn't as bad as they thought. I'm fine now.»

Jemison leaned back with a sigh. «So it's one last mission, eh, before they close down the show? It'll have to be a quick one if you're going to be back before the PM's boys come in the morning to pull our plug once and for all.»

«In the morning? Yes, quite.» This was the first Richard had heard of the new deadline, but he did not let his surprise show. Inwardly he was asking himself, Does that change my plans? No, I can't let it.

Jemison said, «I'll tell Lord Leighton you're here.» He leaned forward, reaching for the intercom button.

Richard snatched the tranquilizer pistol from its sack and pulled the trigger. There was a snick like the small explosive hiss of an angry cat. The dart lodged in Jemison's neck.

Jemison looked toward Richard with amazement, then his eyes clouded and he began to slip forward out of his chair. Richard sprang forward and caught him, carefully lowering him onto the desk, head pillowed on arms. They'll think you're asleep, Richard mused with grim amusement. That's nothing unusual around here. Still, someone might appear at any moment and try to wake him, and then all hell would break loose.

Richard sprinted from the foyer and down a series of long door-lined corridors. Even for this late hour, the rooms along the hall were unusually silent, as if the project had already shut down. Why would anyone work, knowing it was all for nothing?

But the electronic sensors were still on duty no doubt, tracking his every step, weighing him, measuring him, listening to his heartbeat, his breathing, identifying him as one of those few men who could walk these passageways without setting off an alarm. At the end of the final passage a massive door slid open, cued by the electronic surveillance system, and he entered the central computer complex.

The tiny blinking lights on the consoles indicated that the computers were not active, but were on standby. The lighting in the room was muted, but he could make out a glint of chrome here, a smooth plastic surface there, a maze of matt green cabinets covered with dials, switches and lights, with an occasional cathode ray tube, green-glowing like an otherworldly television screen.