“Tumbling them, I would think,” Karl said. He had come in quietly with Fred just behind. “Alfvén waves can nonlinearly decay into waves short enough to be of the same size as the coins. That tumbles them and can kill their navigation.”

“And maybe turn them off, too,” Fred added.

Karl pointed to the wave sequences. “They spread out from the jet, notice. An example of what my language has a single word for—Vernichtungswille: the desire to annihilate.”

“So this is the Folk reply to our first negotiation?” Ayaan Ali asked.

“Looks like,” Fred said. “Say, what’s that?” The back-time display ran into earlier hours, and Fred reached over to freeze it, march it forward. As he did, a blue wave rushed across the entire display space. He backtracked it, shifting out to larger frames. “Look, it traces back to the jet. What’s blue mean?”

“High-energy ions.” Ayaan Ali thumbed the resolution until they could make out a snarl in the jet itself. It was a knot of magnetic stresses that tightened, fed by smaller curls of magnetic flux that rushed outward along the jet.

“Look,” Fred said. “Kinks came purling along the jet, moving fast. They converged in that knot, and—here comes the blue.”

Karl nodded. “From that we get the Alfvén waves. Very neat, really. They can control the magnetic fields in their jet, focus them.”

“To kill our coins.” Redwing looked around at them. “To show us what they can do.”

A silence as they looked at him, as if to say, What do we do?

“Officers of the bridge, I want you to fly a small satellite over the rim of the Bowl. We haven’t got any recon of the outside of this thing, and Ayaan Ali reports that we got a stray signal from Cliff’s team just hours ago. It was text only, said they were under the mirror zone. If we can put a relay sat within range of them, on the outside, maybe we can make a stable link.”

Fred looked at Redwing for a long moment. “You want to risk a satellite?”

“I think we need to know how far these Folk will go,” Redwing said. He kept his tone mild and his face blank.

“As for further measures, I have a brief from Karl”—giving him a nod—“and we will meet in the mess at eight hundred hours to discuss it.” A pause to let this sink in. Time to go public, he figured. “Dismissed.”

*   *   *

He started the meeting with news. Ayaan Ali delivered it, standing beside an image that flickered onto their wall screen. All exec crew were arrayed around the biggest table on the starship, coffees smartly set in front of them, uniforms fresh pressed from the steamer presser, everybody aware that this was not just another damn crew meet.

Grimly she said, “We launched our satellite toward the nearest Bowl rim. It is a microsat with ion drive, so it accelerated fast. I took it over a mountain range that neighbors the rim edge. See the picture sequence.”

A set of stills ran, in time jumps that made the craggy mountains below zoom past. Their peaks were in permanent snow despite the constant sunlight. Redwing supposed this meant that the atmosphere was thin there and the outer skin, which they now knew was quite cold, was only a short distance away. The chill of space kept water frozen out.

Now the scene stuttered forward to show the Bowl rim approaching. The sat probe scanned forward, aft, both sides. At the far left edge, the atmospheric film shimmered, keeping air confined. On the left a small bright light appeared.

“I stop it here,” Ayaan Ali said. “Note the near-UV burst on this view. It appeared within a microsecond frame, apparently a precursor.”

“To…?” Karl wondered.

“This. Next frame.” Ayaan Ali pointed to a bigger white blotch at the same location to the sat probe’s left. Her smile had a sardonic curve. “And that is it.”

Karl asked, “What happened? Where’s the next frame?”

Ayaan Ali gave them a cold smile. “There are no more. It stopped transmitting. Here is an X-ray image of that region. I had it running all during the fly-out, just in case.”

They could make out the dim X-ray images of mountains and Bowl rim. Apparently this came from minor particle impacts of the solar wind. At the very edge of the rim was a hard bright dot. “That’s our probe dying. From spectra and side-scatter analysis, I believe the killing pulse, which we saw the UV precursor of, was a gamma ray beam.”

“From where?” Redwing knew the answer, but he liked to let Ayaan Ali keep the stage.

“That big cannonlike thing farther along the Bowl rim, sir.”

“It’s an X-ray laser?”

Ayaan Ali shook her head. “This image comes from secondary emissions. I can tell by looking at the spectrum. Also, I had a gamma ray detector taking a broader picture. It gave this.”

Another bright dot. This time there was no background at all, just a point in a black field. “The power in this image is five orders of magnitude higher than the X-ray fluence.”

He said flatly. “So we were right. It’s a gamma ray laser.”

Redwing looked at Beth. Ever since she returned, he had asked her to attend tech meetings, reasoning that she might have insights called forth by new events. “As far as I know, we never found a way to go that high in photon energy. Did you see any signs the Folk had tech like that?”

Now Beth shook her head. “Weapons weren’t really around us. Or maybe we didn’t even recognize them as weapons. They didn’t need them, I guess. We were trapped.”

Ayaan Ali said, “Weapons of this class would be very dangerous on a rotating shell world. Blow a hole in the ground and you’re dead.”

Karl said, “There was an Earthside program to develop high-frequency lasers long ago—I mean even before we left—and it never got lasing to gamma energies. At those tiny wavelengths, a laser could focus to very small areas, so you wouldn’t need very much power to blow something to pieces.”

Fred said, “This is bad news. Now we can’t fly a probe over the rim. They can kill any sensors we send out. We’re bottled up.”

“No doubt they expect us to come back to them and ask for a negotiation,” Ayaan Ali said.

“Which we won’t do,” Redwing said. Nobody said anything. Time to change direction. Sometimes that jarred loose a fresh insight. He leaned forward, fingers knitted together. “Beth, do you think that the Folk would ever let us go forward to Glory?”

Beth sighed and looked at the screen, where the explosion of their probe was frozen in time. “They have a very hierarchical society. The big one who interrogated us, Memor, acted as if she owned the world. It’s hard to think they’ll let us go and reach Glory first.”

Ayaan Ali said, “Which we certainly could do, since we won’t be facing their jet backwash.”

Redwing remembered a lecture on alien biospheres during flight training in which someone said, “Humans and animals regard each other across a gulf of mutual incomprehension. With aliens, that has to go double.” Yet here he was trying to figure out the negotiating strategy of an alien mind, immersed in a civilization uncountably old. He let them toss ideas around for a while to get them used to their situation. Sending the probe out to get destroyed had given the right edge to this, he decided. And it had laid to rest any notion that the Folk were bluffing.

“So…” He let the pause grow; they were so quiet, he could hear the whisper of the air circulation. “Let’s send a reply.”

Karl got up to speak and flicked on the wall display. It showed the jet in an extreme view—magnetic field lines in ruby, the tubes of bright plasma they contained glowing orange, the Bowl itself sketched in nearby as abstract lines. “We can fire a shot across their bow. The jet is pretty narrow as it approaches the Knothole. Notice the helical mag fields that funnel and contain the plasma. Very neat.”

Beth said, “So the idea is…?”

“Fly into it. Disturb the jet. Let it flicker around in the Knothole.”