Day 2,100

When the fog rolled in and the otherwise catatonic forests filled with unearthly screeching it was easy to see why the road around the mountain kept being abandoned. Anyone not inside a heavily fortified building might as well leap off into the clouds - they'd face a kinder death than the forest would provide.

Their bodies were never properly recovered, there were always pieces missing. Sometimes we'd find a new piece - a hand or their eyes - hanging from one of the trees near the end of the road or pinned to our doors with quills as long as our legs.

It used to be thought that there were prehistoric porcupines in the forests, as territorial as they were colossal and the roadworks had disturbed their otherwise isolated home. That all changed when one of the site cameras managed to record an attack.

To an outsider it might have been odd to install thermal cameras where the only people around were construction workers and where the wildlife was presumed to be theoretic only but it ended up being the key piece of evidence that got us our secure bunkers.

Now whenever the fog rolls in we can shut everything down and live to see another day instead of hoping they'd take someone else - anyone else but you. We might even live long enough to see what's on the other side of the fog, if there's anything at all.