It presented me with a surprise. Thermocline was present in the Core, just as he had said, but he was no longer among the living. He had become a Stored Mind.
Becoming a Stored Mind is nothing out of the ordinary for a Heechee. It's what all Heechee do when they die, unless they are so terribly unlucky as to die where no one can find them in time for storage, before decay has made it impossible. The only reason I was surprised was that Thermocline had been still quite organic at the time when I left for the Core. It hadn't occurred to me that he would have had the time to age, sicken and die.
Interfacing from a human stored-intelligence setup to the wholly different surround of a Heechee stored mind isn't easy. It took me more than half a second to make my way into Thermocline's surround. I recognized him at once. He was unchanged in appearance from his days on the Wheel, but his surround was a different matter. Basically there wasn't any.
I had not expected that. Every last machine-stored organic intelligence I had ever known, and most of the other varieties of AIs as well, had made itself a comfortable little home base, ranging from my kitchens and Thor Hammerhurler's war-waging HQ to the occasional fully stocked harem. What Thermocline had made for himself wasn't anything like any of those. He was awaiting me in a chamber that was not much more than three meters in any dimension. The walls were a neutral gray, decorated with a couple of Heechee lookplates and very little else. The lighting was subdued and, as far as I could see, sourceless, and the furniture absolutely minimal. That is, there was a sort of recliner for Thermocline himself, on which he sat, or lay, at ease. There was also a straight-backed chair for one visitor. (For one specifically human visitor, I observed. If he had been expecting a Heechee rather than myself I suppose it would have been replaced by one of their perches.)
That was it. Or not quite it. There was something unusual about Thermocline's appearance, and it took me a moment to figure it out. He wasn't wearing that universal Heechee costume accessory, the storage pod that they kept slung between their legs.
Well, of course he wasn't. He no longer required the mild, life-sustaining microwave flux the pods provided for their owners, since he no longer was organically alive. Nor had Thermocline any need to haul his own Ancient Ancestor around with him anymore, since now he himself was one.
Thermocline didn't get up to greet me, or shake my hand. He was definitely welcoming, though. "My dear Marc Antony," he said in his perfect English, acquired in his decades on the Wheel, "what a wonderful surprise! I had reconciled myself to going back to a simulated diet of CHON-food, not to mention the loss of your good company, and I am delighted that you are here. But why did you come to the Core?"
I told him my story, and then I asked him the same question. He gave me the belly-muscle shrug. "My organic body was wearing out," he said. "It was time to become a Stored Mind, and I preferred to do that at home. What about you? Will you be happy here?"
"Will you?"
He made the open-handed gesture of dismissal. "We Heechee live all our lives in the expectation of an afterlife of meditation and service. We are prepared for it." He paused. His facial muscles tightened for a moment, then sagged. "Ah, well, Marc," he said, "enough, as you used to say, of the small talk. Can you guess why I wanted to see you?"
I said warily, "I suppose it has something to do with the security network I've been working on."
Heechee don't laugh, but he made a little hiccoughing sound that came close. "Not at all. It is because of your investigations of our own alarm network that I became aware of your presence and activities, to be sure, but the reason I messaged you was something else. Do you know who Albert Einstein is?"
I knew he was not asking about the ancient human scientist of that name. "Of course. A machine intelligence. At one time he was merely Robinette Broadhead's shipmind, but now they seem to exist as separate individuals."
"Exactly. Indeed, Albert himself has hived off some independently functioning subsystem for particular needs. One of these, an individual named Sigfrid von Shrink, has been quite useful in the case of one of our own people who had suffered mental harm while on duty at your Gateway asteroid—"
"Interesting," I said. Thermocline, as I remembered well, had always liked to talk. "You were saying about Albert?"
"Yes. Albert is not here in the Core, but he sent a message to Sigfrid von Shrink, who passed it on to me. He is troubled about a human person, now machine-stored, whose name is Wan Enrique Santos-Smith. I have learned that at one time you had some dealings with this man. Can you tell me something about him?"
I had no reason to keep still, so I told him about our voyage to the planet called Arabella, Harry, me and the tank full of Foe. He listened attentively, then pursed his thin Heechee lips. "Is Albert aware of this?" he asked.
"I don't know. I understand Albert is aware of most things," I told him, "but perhaps I should send him the data."
He inclined his skull-like head. "I will do so myself, if you don't mind, by informing Dr. von Shrink. Usefully, he is in regular contact with the organic human being, Gelle-Klara Moynlin. She had at one time been a person of special sexual, though nongenerative, interest to Robinette Broadhead himself, and, as it happened, at a different time, to Wan himself as well."
"The sexual concerns of organic humans are often confusing," I observed.
"Indeed so. Klara's shipmind will also be informed."
"Hypatia, yes. I have had conversations with her. A quite high-performing person."
"Yes," he said absently. He seemed to be having some sort of internal dispute, his expression changing moment by moment from polite inquiry to concern—even to worry.
I didn't want to take time for Thermocline to settle his interior problems. "Is something troubling you?"
He shook his head. "Ah, Marc, I can't keep much from you. Tell me, do you remember the strange behavior of that star of the external galaxy, the one you call Fomalhaut?"
"Fomalhaut," I repeated—not so much stalling as an organic human might, while he took time to cudgel his memory, but achieving the same effect as I accessed some of those parts of my memory files not usually pertinent to my day-by-day existence. "Of course. The star that went supernova a few days—that is, some hundreds of external years—ago."
"Exactly," Thermocline said heavily. "However, Marc, it was not a normal supernova. It was caused by our intervention."
He stopped there, gazing at me with a troubled expression, perhaps maybe waiting for me to ask what kind of "intervention" he was talking about. I didn't have to, though. The pieces fell into place, and I knew.
"Thermocline," I said, "when we infiltrated Wan's fortress on the planet Arabella the first thing they asked me was whether I knew how to make a star explode. So when we got back, I asked Thor Hammerhurler. He said he had heard that you people might have been working on something like that, but it didn't seem to be operational."
That had an effect on Thermocline. His belly muscles writhed and tautened. "Yes," he said sadly, "it wasn't operational at that time. But it is now." He did sigh that time, a tribute to his mastery of Earth-human ways. "The device is a variation on the order disrupter that is used to penetrate black holes. By discharging a star's gravitation it would make the star fly apart. You see," he said earnestly, "it was never intended for use on actual stars, especially any with, or in the vicinity of, inhabited planets. You remember how the Foe live?"