By the end of the twenty third century, mankind had colonised the solar system and was starting to receive telemetry from probes sent to nearby stars. Analysis of this information along with data from a newly constructed solar lens around the sun caused great excitement, as it indicated dozens if not hundreds of worlds with a high habitability index within a couple of hundred light years of earth.

Most were pristine and without a biosphere, but some showed strong indications of life! And so began the great exodus, as humanity constructed vast interstellar arks, needles thousands of kilometers long, mostly composed of magnetic containment for antimatter to the rear and a forward section the size of a small city for colonists behind an enormous front buffer made up of hardened rock ice.

These remarkable vessels were the crown jewels of centuries of technological advancement in space travel technology, built so that after they had completed their journeys, they could restock their antimatter supplies by close orbit of their target star, rebuild the front buffers from local materials, and move on if need be.

While time on earth passed at its usual pace, for the colonists a hundred years could pass in a decade, so mankind expanded far and wide. By the twenty sixth century, almost ninety systems were in various stages of colonisation. Each system sent a steady stream of news, scientific advancements, entertainment and other information to the others by massive outer system radio beacons, keeping everyone in contact.

Then something strange began to happen. In Alpha Cephei, also named Alderamin, communication techs began to notice that signals had stopped from one colony. No notice, no warning, they simply... stopped. Suspecting a technical error due to interference the Alderaminers switched off all of their own communication broadcasts but the signal didn't reappear.

Then another colony went dark. And another. And another. In swift succession they lost contact with twenty colonies at all points of the sky. Alderamin colonial governments still hadn't reactivated their comms beacons, but were watching with increasing trepidation. Examination of the last transmissions of the now-silent systems revealed something even stranger - much of what they'd been sending for the past year was reconfigured recordings of much earlier broadcasts!

And even more colonies dropped out of contact, one by one until only earth and Alderamin remained.

Then earth's beacons went silent.

After that no more human-origin signals arrived, except one, a garbled transmission apparently directed in widebeam across the galaxy from colony ark Green Aurignon. It was weak and scattered, but commtechs managed to piece together the following partial sentence:

"The lights... everywhere... dead eyes... vital to wash... heavier than mucic acid works, around the cables... and antimat... children! Oh God what... they... coming... never forget yourselves..."