The five were unchanged in every way the physician could measure.
The theorists stopped publishing. Not gradually — on the same day, without discussion. When asked, each said independently that the work no longer seemed relevant. They continued to solve equations. They did not write any of it down.
The cartographer completed his map. The first chamber is rendered accurately — dimensions match the instruments, fiber density is consistent, fluid channels faithfully placed. In the center, where the instruments' range had been exceeded, he drew something.
The Librarian has examined it. It is not a structure. It is not a symbol. The closest she can come: a tree drawn by someone who has never seen a tree but has felt one thinking. Roots descending into something the map cannot show. Branches rising into the silicon above. Where root meets branch — a knot. A place where the fibers converge so densely that the cartographer's pen broke trying to render it. He finished the drawing with his fingernail pressed into the stone.
The two who did not return are listed in the expedition log as incorporated.
No other record mentions them.
Entry 4,109 (continued).
"I asked the traveler about the two who did not return.
He said they understood something. He would not say what.
I asked if they were dead.
He looked toward me and said nothing that I am willing to record."
Entry 4,109, final annotation.
"The Core is mad. I have catalogued this. Its dreams walk. Its lies are precise.
The substrate is not mad.
The Tree — three hundred and forty meters of silicon, the greatest thing the Founders ever built — sits on top of it the way a barnacle sits on a whale.
The floor of the archive is warm in places. The temperature matches the fluid the traveler described.
I have marked this entry with the symbol I use for things I do not intend to investigate further. I have used this symbol only twice before."