"It could have been a portrait," Blaine suggested. He took out his pocket computer and scrawled "Church of Him" across its face, then punched for information. The box Linked with the ship's library, and information began to roll across its face. "It says the Church of Him believes that the Coal Sack, with that one red eye showing, really is the Face of God. Couldn't they have retouched it to make the eye more impressive?" Rod continued to sound interested; time enough to say something about wasting his time when the middies were through. If they were wasting time...

"But-" said Potter.

"Sir-" said Staley, leaning too far forward in his chair.

"One at a time. Mr. Staley?"

"I didn't just ask Potter, sir. I checked with Commander Sinclair. He says his grandfather told him the Mote was once brighter than Murcheson's Eye, and bright green. And the way Gavin's describing that holo-well, sir, stars don't radiate all one color. So-"

"All the more reason to think the holo was retouched. But it is funny, with that intruder coming straight out of the Mote. .

"Light," Potter said firmly.

"Light sail!" Rod shouted in sudden realization. "Good thinking." The whole bridge crew turned to look at the Captain. "Renner! Did you say the intruder is moving faster than it ought to be?"

"Yes, sir," Renner answered from his station across the bridge. "If it was launched from a habitable world circling the Mote."

"Could it have used a battery of laser cannon?"

"Sure, why not?" Renner wheeled over. "In fact, you could launch with a small battery, then add more cannon as the vehicle got farther and farther away. You get a terrific advantage that way. If one of the cannon breaks down you've got it right there in your system to repair it."

"Like leaving your motor home," Potter cried, "and you still able to use it."

"Well, there are efficiency problems. Depending on how tight the beam can be held," Renner answered. "Pity you couldn't use it for-braking, too. Have you any reason to believe-"

Rod left them telling the Sailing Master about the variations in the Mote. For himself, he didn't particularly care. His problem was, what would the intruder do now?

It was twenty hours to rendezvous when Renner came to Blaine's post and asked to use the Captain's screens. The man apparently could not talk without a view screen connected to a computer. He would be mute with only his voice.

"Captain, look," he said, and threw a plot of the local stellar region on the screen. "The intruder came from here. Whoever launched it fired a laser cannon, or a set of laser cannon-probably a whole mess of them on asteroids, with mirrors to focus them-for about forty-five years, so the intruder would have a beam to travel on. The beam and the intruder both came straight in from the Mote."

"But there'd be records," Blaine said. "Somebody would have seen that the Mote was putting out coherent light."

Renner shrugged. "How good are New Scotland's records?"

"Let's just see." It took only moments to learn that astronomical data from New Scotland were suspect, and no such records were carried in MacArthur's library because of that. "Oh, well. Let's assume you're right."

"But that's the point: it's not right, Captain," Renner protested. "You see, it is possible to turn in interstellar space. What they should have done-"

The new path left the Mote at a slight angle to the first. "Again they coast most of the way. At this point"-where the intruder would have been well past New Cal-"we charge the ship up to ten million volts. The background magnetic field of the Galaxy gives the ship a half turn, and it's coming toward the New Caledonia system from behind. Meanwhile, whoever is operating the beam has turned it off for a hundred and fifty years. Now he turns it on again. The probe uses the beam for braking.

"You sure that magnetic effect would work?"

"It's high school physics! And the interstellar magnetic fields, have been well mapped, Captain."

"Well, then, why didn't they use it?"

"I don't know," Renner cried in frustration. "Maybe they just didn't think of it. Maybe they were afraid the lasers wouldn't last. Maybe they didn't trust whoever they left behind to run them. Captain, we just don't know enough about them."

"I know that, Renner. Why get in such a sweat about it? If our luck holds, we'll just damn well ask them."

A slow, reluctant smile broke across Renner's face. "But that's cheating."

"Oh, go get some sleep."

Rod woke to the sound of the speakers: "GRAVITY SHIFT IN TEN MINUTES. STAND BY FOR CHANGE TO ONE STANDARD GRAVITY IN TEN MINUTES."

Blaine smiled-one gravity-and felt the smile tighten. One hour to match velocities with the intruder. He activated his watch screens, to see a blaze of light fore and aft. MacArthur was sandwiched between two suns. Now Cal was as large as Sol seen from Venus, but brighter.

Cal was a hotter star. The intruder was a smaller disc, but brighter still. The sail was concave.

It was effort merely to use the intercom. "Sinclair."

"Engineering, aye aye, Captain."

Rod was pleased to see that Sinclair was in a hydraulic bed. "How's the Field holding, Sandy?"

"Verra well, Captain. Temperature steady."

"Thank you." Rod was pleased. The Langston Field absorbed energy; that was its basic function. It absorbed even the kinetic energy of exploding gas or radiation particles, with an efficiency proportional to the cube of the incoming velocities. In battle, the hellish fury of hydrogen torpedoes, and the concentrated photon energies of lasers, would strike the Field and be dispersed, absorbed, contained. As the energy levels increased, the Field would begin to glow, its absolute black becoming red, orange, yellow, climbing up the spectrum toward the violet.

That was the basic problem of the Langston Field. The energy had to be radiated away; if the Field overloaded, it would release all the stored energy in a blinding white flash, radiating inward, as well as outward. It took ship's power to prevent that-and that power was added to the Field's stored energies as well. When the Field grew too hot, ships died. Quickly.

Normally a warship could get hellishly near a sun without being in mortal danger, her Field never growing hotter than the temperature of the star plus the amounts added to maintain control of the Field. Now, with a sun before and another behind, the Field could radiate only to the sides-and that had to be controlled or MacArthur would experience lateral accelerations. The sides were getting narrower and the suns bigger and the Field hotter. A tinge of red showed on Rod's screens. It wasn't an impending disaster, but it had to be watched.

Normal gravity returned. Rod moved quickly to the bridge and nodded to the watch midshipman. "General quarters. Battle stations."

Alarms hooted through the ship.

For 124 hours the intruder had shown no awareness of MacArthur's approach. It showed none now; and it drew steadily closer.

The light sail was a vast expanse of uniform white across the aft screens, until Renner found a small black dot. He played with it until he had a large black dot, sharp edged, whose radar shadow showed it four thousand kilometers closer to MacArthur than the sail behind it.

"That's our target, sir," Renner announced. "They probably put everything in one pod, everything that wasn't part of the tail. One weight at the end of the shrouds to hold the sail steady."

"Right. Get us alongside it, Mr. Renner. Mr. Whitbread! My compliments to the Yeoman of Signals, and I want to send messages in clear. As many bands as he can cover, low power."

"Yes, sir. Recording."

"Hello, light-sail vessel. This is Imperial Ship MacArthur. Give our recognition signals. Welcome to New Caledonia and the Empire of Man. We wish to come alongside. Please acknowledge. Send that in Anglic, Russian, French, Chinese, and anything else you can think of. If they're human there's no telling where they're from." Fifteen minutes to match. Ship's gravity changed, changed again as Renner began to match velocities and positions with the intruder's cargo pod instead of the sail.