"What's that?"

"Sunlight, sir. On Earth, it only penetrates about one hundred fifty meters into the ocean. Actually, most light goes no deeper than the top ten meters . . . but by the time you reach one hundred fifty meters, it's completely dark. Here, with the red sunlight, it's probably less . . . and under the ice, on the nightside of the planet . . . well, there's no light entering the ocean at all."

"So?" Walthers demanded. "What are you getting at?"

"Eyes," I replied. "The cuttlewhales have eyes. Six of them. If they evolved far enough down that they developed under high pressures, why do they have eyes?"

"Those might not be eyes," Ortega said, but he sounded unsure. "I wish you could have picked one of them up and brought it along. We might know more. . . ."

"Sorry, sir, but I wasn't going to wait around out there on the ice any longer than I absolutely had to. But . . . I wonder. If the cuttlewhales were designed, if they were manufactured somehow by another intelligence . . . maybe they were given eyes in order to explore the surface remotely."

"Huh," Garner said. "Like our remote probes."

"That is an enormous leap, Carlyle," Walthers said. "Kind of a leap of faith, isn't it?"

"I suppose so, sir. But it's something to think about."

"Over a long-enough period of time," Ortega said, thoughtful, "a deep-benthic life form might move to the surface and evolve vision . . . then migrate back to the depths. . . ."

I shrugged and spread my hands. "Look, all of this is pure speculation at this point. I'm just suggesting that we should keep in mind the possibility that the cuttlewhales are . . . artificial. That would certainly have an effect on our mission, wouldn't it?"

"To say the least," Montgomery said. She still looked like she was in shock. "Just where would they have evolved in Abyssworld's ocean? Or . . . where would they have been created, if that's the right term? How far down?"

I shook my head. I had numbers, but no proof, nothing solid. "Well, you need a water pressure of around a thousand atmospheres to turn ordinary water into Ice VII. That's not too extreme, as exotic ices go. You find that at a depth of ten thousand meters on Earth . . . or about eleven thousand meters on Abyssworld. Eleven kilometers down . . ."

"That's only a thousandth of the way to the sea floor," Walthers pointed out.

"My God. What are the pressures like at the bottom of Abyssworld's ocean?" Ortega asked.

"I was wondering about that myself, sir," I replied, "and I did some simple calcs. On Earth, water pressure increases by one atmosphere-that's over a hundred thousand Pascals-for every ten meters you descend. Abyssworld's gravity is only ninety-one percent of Earth's, and there's a direct one-to-one correlation between the weight of the water and the pressure it exerts, so call it nine hundred ten thousand atmospheres.

"That's a skull-crushing thousand tons or so pressing down on every square centimeter."

"What happens to water ice at that depth?" Garner asked.

"I don't know," I said. "Nobody does. One possibility is that the bottom of Abyssworld's ocean-maybe even the bottom three or four or five thousand kilometers of it-isn't liquid water anymore. It might be a highly compressed slurry or ice-slush composed of several exotic ices, kind of like the jelly Dr. Ortega mentioned. Heat from the planet's core might create convection currents, so it would be constantly circulating. It certainly would be a very strange environment. We don't know enough, though, to know how strange."

"What kind of life might we find down there?" Montgomery asked.

It was a rhetorical question, I knew, but I couldn't resist answering. I'd been wondering a lot about the same thing.

"Just about anything is possible, ma'am," I told her. "With heat from the planet's core, with water and various nutrients, salts, metals, stuff like that from sea-floor vents, there's no telling what might have evolved down there."

For the first time in our discussion, one of the Brocs chimed in, its words written out by the ship's AI within our in-heads. IT IS VITAL THAT YOU REMEMBER, D'drevah wrote, THAT MOST LIFE IN THE UNIVERSE LIVES IN PLACES LIKE ABYSSWORLD'S DEPTHS, AND NOT NAKEDLY EXPOSED ON THE ROCKY SURFACES OF PLANETS LIKE M'GAT OR EARTH.

I thought again about the Medusae of Europa.

"Okay," Walthers said. "That's all well and good, but I don't see how it will affect us. We don't have the technology to explore such depths."

"We might be able to probe those depths with sonar," Montgomery suggested.

"I submit, madam," Garner's voice replied, "that it was sonar that attracted the cuttlewhales in the first place. They appeared almost immediately after the Marines began using high-power, low-frequency sonar through the ice. It's possible that Murdock Base was destroyed when they tried the same thing. Perhaps we should leave well enough alone."

"I have a question," Ortega said. "If the cuttlewhales were formed at a pressure of a thousand atmospheres, why don't they explode on the surface? You know, like deep-sea fish brought up from extreme depths?"

"Actually, sir, the ones we encountered on the surface were beginning to degrade," I told him. "I don't think they can survive very long at surface temperatures and pressures. But those fish you mention explode because gas in their swim bladders expands as they're brought to the surface-expands a lot. I think the cuttlewhales must have some sort of internal mechanism that keeps their internal pressure balanced with what's outside. We know they have a gullet . . . but that might close completely at high pressure. And we don't know what they use for a heart. Not a conventional pump like ours, certainly. They're too big. They may rely on seawater diffusing throughout their bodies."

"Solid-state bodies, then," Ortega mused.

"Essentially, yes."

"Robots," Hancock said.

"At the surface, or in warm temperatures," I went on, "Ice VII starts to . . . unravel is the best word I can think of. It requires high pressure to keep the ice crystals in that configuration, with the interpenetrating lattices . . . but when the pressure goes away, it doesn't explode. It just kind of oozes into the new state."

"The question remains," Walthers said, "as to whether any of this helps us at all. Can we even hope to talk to these things? Or to . . . to their manufacturers?"

"A suggestion, sir?"

"Go ahead."

"The cuttlewhales are . . . electrical in nature. So are we, of course, but not in the same way. Humans generate what is essentially weak electrical currents through chemistry-through exchanges of positive or negative ions at neural synapses or in muscle fibers, for instance. That's what we're reading with an EEG or an EKG.

"But cuttlewhales seem to work because of actual electrical currents-moving electrons-throughout their bodies. I don't know how that would work, but the ferroelectric effect of the Ice IX strands would support a fairly high voltage."

"Great," Hancock said. "Not only can they crush us, they can electrocute us! Is that what you're saying?"

"Probably not that much voltage, Gunny. But enough to create a pretty strong electrical field in the water. Especially in saltwater. I haven't analyzed it yet, but I suspect that Abyssworld's ocean is pretty salty."

Salts, I thought, would be spewed into that ocean through volcanic vents. The minerals I'd detected inside the cuttlewhale sample-the sulfur and all the rest-proved that there were a lot of other elements in the ocean, even though there was so much of it.

"What's your point, Carlyle?" Walthers asked.

"Our most important senses," I replied, "are vision and hearing, okay? Cuttlewhales live in absolute darkness. They probably rely on sound-I like your idea about them being attracted by the sonar pulses, by the way, sir-but they might also rely on the electrical sense."

"Electrical sense?" Walthers asked. "What's that?"

"Some animals on Earth can sense electrical fields," Ortega explained. "Or they can passively sense other animals moving through them. Electric eels can do this, for instance. Sharks and rays. Certain dolphins. Even a funny little animal called the platypus. It's called electroreception, and it's as important to those animals as any of our senses are to us."

"If cuttlewhales can detect electrical fields," I added, "maybe that's how they communicate. Not by sound . . . or not entirely, but by modulating electrical signals in the water."

"That," Montgomery said with feeling, "is brilliant!"

"I wonder if Selby and his people on Europa have thought of that," Ortega said. He laughed. "You need to write that up in a paper, Carlyle. Publish it in the Journal of Exobiology. I think you're onto something big here. . . ."

"Well, we need to detect those signals first," I said. The sudden burst of attention from the two scientists was a bit embarrassing.

"Easy enough to do," Ortega said. "We have a submarine . . . a means of approaching a cuttlewhale in its own environment."

"Dr. Ortega, you have got to be crazy!" Walthers exclaimed. "You saw what they did on the surface. . . ."

"Our entire reason for making this journey," Ortega said, "was threefold. We were to look for Sub-zero survivors, to rescue them if necessary, and we were to attempt communication with any intelligent Abyssworld inhabitants. At this point, I submit, we are still oh for three. Young Carlyle, here, has shown us a means of improving our score."

"It seems unlikely at this point that we will find survivors from the base," Walthers pointed out. "And I have the safety of the ship and passengers to consider."

"Ortega's right," Garner's voice said over the electronic link. "I thought Marines were supposed to fight . . . not turn tail and run!"

"I object to that, Chief," Kemmerer said. "We are here to provide security for the operation, not involve ourselves in pointless bloodshed."

" 'Visit exotic, distant worlds,' " Garner said, " 'meet strange, alien life forms . . .' " He laughed, a chilling sound.

Visit exotic, distant worlds, meet strange alien life forms, and kill them. . . .

I decided that the chief's arm was hurting him. It was a joke dating back in a slightly different form to pre-spaceflight days. It did an injustice to the Corps, I thought, maintaining the ancient and vicious fiction that Marines were only interested in killing.

It's true that they are very, very good at killing, certainly. But another ancient adage referring to the Marines holds that while there are no worse enemies, there are no better friends.

"Lieutenant Kemmerer?" Walthers said. "What do you think about returning to the surface? Or trying to contact cuttlewhales?"

She shrugged. "The Marines will go where you send us, Captain," she said. She emphasized Walther's position as ship captain, rather than his rank of lieutenant. Until Summerlee returned to duty, he was the one with the final say. Not the Marines, not the doctors, and not the science and technical staff.

"D'deen? D'nah?" Walthers called, raising his voice. "You are the closest we have to xenosapient experts on board. What's your opinion?"

THE GYKR ARE A ROGUE INTELLIGENCE, D'deen wrote, from a rogue world between the stars. THEY DO NOT FOLLOW . . . YOU WOULD CALL THEM . . . THE RULES. THEY MAY HAVE THEIR OWN MOTIVES FOR ATTEMPTING CONTACT WITH THE NATIVE ABYSSAL LIFE. WE SUBMIT THAT YOU MAY WISH TO ESTABLISH SUCH CONTACT FIRST.

"I'm more concerned about the Gykr as a military force," Walthers said slowly, "than I am about talking with the native life. They will be back. The question is when. What do we do about that?"

"Not really a major problem, sir," Garner said. "If we land at a different area . . . build a nanomatrix habitat, then we could keep Haldane in orbit. With nanoflage on the outer surface of the base, the Guckers shouldn't see us if they do show up . . . and it is a damned big planet. If they show up, Haldane could run for Earth, maybe come back with reinforcements. And we stay on the planet and try to talk to Carlyle's electric whales."

My electric whales.

But most at the table agreed then, that trying to communicate with the beasts was vitally important. The Gykrs had turned it into a race.

We would stay.

And we would try to make contact with the locals.

Chapter Sixteen.

Haldane touched down once again on the icecap about twelve kilometers from the former site of Murdock Base. We used robotic vehicles to unload about forty tons of rawmat onto the ice and spread it out in a thin layer. Rawmat-raw materials for nanotechnic construction-is a balanced mix of basic elements: iron, aluminum, silicon, copper, gold, carbon, tungsten, and a dozen other elements in powder form to give it the greatest possible surface area. The most critical problem was keeping all of that fine-grained powder from being blown away by the blustery winds gusting out of the west. We managed that by mixing the stuff with water as it came out of the robots' hoppers. The water froze and nailed the rawmat down in a thin, black carpet over the ice. Nanobots don't care if their raw materials are loose, or frozen inside solid water.

Once the powders were down, we released a few trillion nanobots programmed for materials construction, beamed them an architectural plan, and in about two hours they'd grown our new base from the component atoms. On Earth, we build four-kilometer-tall towers of spun glasstic or ferrocrete from the carbon, hydrogen, silica, and metals right there in the dirt and rock of the construction site. The only native raw materials here, though, were the oxygen and hydrogen of the water ice, plus some traces of carbon and nitrogen from the CO2, CH4, and NH3 in the atmosphere or trapped within the ice. When the main dome was up, though, we used drilling bots inside to tunnel down through the ice to reach the seawater below, and were able to reach quite a few more elements dissolved in the water.

We began manufacturing the base's interior gas mix then. The oxygen came from the water, of course . . . but the nitrogen was tougher, since the only source we had for N2 was the ammonia that made up about 3 percent of the planetary atmosphere. We grew the atmosphere processing machinery for that, and seasoned the mix with three hundred parts per million of CO2. As counter-intuitive as it seems, too little carbon dioxide in the blood-a medical condition called hypocapnia-can be as bad as too much.

We continued to wear breathing masks inside the base for a time, however, just to be on the safe side. There was a danger, a small one, that toxins or organic molecules had been mixed in with the surface ice, and we were taking no chances with toxic fumes or anaphylaxis. The base atmospheric regulators would continue to scrub the gas mix until we were sure there was no chance of contamination.

While some of us worked on making the new facility habitable, another team from the Haldane melted a hundred-meter-wide hole in the ice outside, extending it to connect with the open water beyond the edge of the icecap. Haldane lifted on her spin-floaters and slowly lowered the Walsh from her cargo bay and into the dark water. Walsh, with her compressed-matter construction, was designed to fly through the water, rather than control her depth with ballast tanks. To keep her from sinking as soon as they dropped her into the water, Haldane's people had rigged her with quantum floaters that were kept running continually, holding the Walsh steady at her moorings.

By that time, we were putting the finishing touches on the base-one large dome with four smaller subsidiary domes evenly spaced around the perimeter. After laying down an airlock cylinder extending some distance from the main hab dome, Haldane was able to pull up several million liters of water and dump it over the outside of the facility, letting it freeze in uneven masses to disguise the regular and artificial look of the place. A molecule-thin film of specially programmed nanoflage went over that, breaking up the outlines and bending incoming light in order to create the illusion of completely natural pressure ridge.

If the Gykr came by now, they wouldn't be able to see us.

We spent another five hours transferring tons more rawmat off of the Haldane and into both the hab modules and the submarine. This was mostly carbon, raw material for the nanufactories on the sub and in the base. Combined with hydrogen, oxygen, nitrogen, and numerous trace elements taken from the sea and atmosphere, this would become our food supply for the next several months. If Haldane had to abandon us, we would be on our own for at least a month before she could return with reinforcements.

Quite apart from that, however, it would take time to descend into the depths. Sierra Five was at a depth of around a thousand kilometers. With a maximum descent rate of around ten meters per second, it would take us a bit less than thirty hours to reach Sierra Five. If we wanted to venture into the real depths of Abyssworld, though, it was going to take a while-more than twelve days to descend eleven thousand kilometers, and longer to come back up.

The chances were good that we would not be going that deep . . . and the experts weren't even certain that Walsh would survive such a dive. But we would need to take plenty of food along just to be on the safe side. Fortunately, air and water were easily enough pulled from the surrounding ocean.

The Walsh was large enough to carry seven people-ten or twelve if they were very friendly. How many of us would actually be descending into the abyss was yet to be determined.

And that was the purpose of our final meeting on Haldane's mess deck, a few hours before we would be ready to make the descent. Eleven of us were in physical attendance this time, and quite a few more were virtually present, listening in over the ship's computer Net. The three Brocs were on-line . . . and so was Chief Garner, who was still recovering from his burn in sick bay.

"Doc! How is the captain doing?" Walthers asked with no preamble.

"We're bringing her up out of deep sedation," I told him. "That'll take a couple more hours. Aside from that, she's fine . . . but we don't have the medical tech on board Haldane to deal with her prosthesis failure."

"You mean we have to get her back to Earth."

I nodded. "We could give her a rough-and-ready implant, the sort of thing we'd do for someone who'd lost all connectivity with a bad accident or something like a severe stroke. But for full function, she'll need to have her implant traced almost molecule by molecule, and a lot of it will have to be dissolved, then rechelated as new circuitry."

That kind of work was incredibly delicate and fussy, not the sort of thing you want to try in the field at all. Fortunately, there was no need. I knew Walthers was uncomfortable being in command, but he could run the ship until we got the captain back home.

He sighed. "Okay. I guess I'm it. What about Kirchner?"

That was a tougher question. Kirchner had been worrying me more than anything else in the department. Before his final break, I'd been doing more private research, trying to plug in psychiatric symptoms. For a while, there, I'd begun wondering about Asperger's disorder, and the AI had been throwing that out as well. I'd doubted that diagnosis, however. Asperger's is part of the autism spectrum, tends to have a gradual onset, and is characterized not only by problems with social interaction but by restricted patterns of interests or behavior as well. And though we don't know yet what causes Asperger's, it appears to be a developmental problem, probably with genetic roots. You're not likely to develop it at 108.

Which had brought me back to schizophrenia. That diagnosis had been looking unlikely as well. He had the problems with social responsiveness and interpersonal dysfunction, but there'd been no sign of the usual disorganized thinking or speech. And we couldn't get inside his head to tell if he was delusional, truly paranoid, or suffering from auditory hallucinations . . . the "voices in the head" so characteristic of the disease. Besides, classic schizophrenia usually begins manifesting before the age of 30, not in old age.

But then he'd gone and pulled a gun, used the gun, and started spewing word salad.

That pretty much confirmed the schizophrenia diagnosis . . . but not completely. Damn it, we were still so helpless in the face of psychiatric pathology. Broken legs, epidural hematomas, even a spinal fracture . . . that stuff is child's play compared to figuring out what's gone wrong inside a person's mind.

"The doctor," I said, "is in a tube down in Medical. We'll be keeping him in a deep coma until we can get him back to Earth for proper treatment."

"Yes, but what's wrong with him?"

"Our provisional diagnosis is paranoid schizophrenia . . . but I need to emphasize that that's provisional, meaning we're really not sure. His genome shows none of the usual markers predicting that disease, he has no family history or personal record of either schizophrenia or schizoid personality disorder, and those diseases are just not that likely to come out of nowhere."

"Does it make a difference?"