Betrayer of Worlds by Larry Niven, Edward M. Lerner

history dump. Voice would be recording; Louis only half listened, trying to see the bigger picture. No one knew exactly when the Lost Colony fell, but it was around 2400. Close to four centuries ago. A battle to the death then between Pak and human protectors could hardly be cause for alarm now.
    Louis broke into the recitation, even though it would take Ausfaller a while to notice. “So there’s been another Pak invasion, this one threatening the Fleet or New Terra. That’s the archive this Roland broke into.”
    “The new Pak advance threatened both our worlds,” Nessus said, “but it has since been deflected. They are going around us. Sigmund, I do not understand your alarm.”
    “I’m almost there,” Ausfaller said. “There is a final bit of background to cover. Brennan’s cold-blooded slaughter on Home was not an isolated event. On the Pak home world, they had developed whole institutions around childless protectors needing a reason to live. If you convinced yourself you served the whole Pak race, you might get past losing your descendants. Phssthpok spent his life hunting for Earth because
he
had become childless.
    “One such institution was the Library, the fail-safe repository of Pak knowledge. Whenever clan rivalries got out of hand and civilizations fell, the Library helped the survivors rebuild. Lots of childless Pak ended up serving the Library.
    “After Phssthpok set out, some Pak explorer discovered the leading edge of the radiation erupting from the galactic core explosion. Pakhome is near the core, and Pak don’t have hyperdrive technology. Everyone who could get onto a ramscoop did. Everyone who didn’t have a ship did his best to steal one. Once the ships were gone, everyone left behind fought over the dwindling resources with which to build more.
    “So you’re right, Louis. Pak hordes came toward the Fleet and New Terra. And yes, the Pak fleets were deflected away from our worlds, in what I called the Pak War, although Nessus glossed over a lot.”
    Glossed over what? Nessus was plucking at his mane again, Louis noticed, just as he had noticed that the Puppeteer did not want Louis to mention the Gw’oth. Meanwhile Ausfaller worried about Achilles’ disappearance, while Nessus worried about Achilles’ feud with the Gw’oth. And the New Terran spy gone bad, this Roland fellow, broke into Pak War records before vanishing, presumably in league with Achilles. Round and round the clues went, the Gw’oth surely somehow at the heart of things.
    “That’s about it,” Ausfaller was saying. “Picture thousands of childless Pak, the keepers of an ancient Library. Safeguarding knowledge on a doomed world no longer gives them a reason to live. But if they could carry away that knowledge . . .”
    Taking a long swallow from a drink bulb of coffee, Louis tried to take it in. Thousands of childless protectors and an ancient Library—they would need a lot of ships. Protectors
with
family would take those ships if they could. Could even thousands of Librarians have prevailed against a world of desperate refugees?
    Not without help. Not without, like Brennan on Home, ruthlessly slaughtering whole clans to turn surviving protectors into allies. Either there was no Librarian fleet or . . .
    “There’s an enormous armada of Librarians, isn’t there?” Louis said. “It’s carrying the best of Pak technology. Your bad apple knows everything
you
know about the Library, and he’s leading Achilles right to it.”
    Louis glanced at Nessus. None of the fine print committed Louis to keeping Puppeteer secrets. “And Achilles will use whatever Pak technology he can steal against the Gw’oth. And to make himself Hindmost—if he doesn’t get everyone killed first.”
    Nessus bleated like a bagpipe that had been dropkicked.
    A few seconds later, long before Louis’s speculation could have reached him, Ausfaller said, “I fear that Achilles is going after the Library, hoping touse Pak technology to