An Unwelcome Sight

We left the spire vacant for generations. Nobody entered… nobody even went close enough to see where it met the earth.
But last night, just by chance, we passed close enough to see it above the trees — and there were lights in the windows.
Who would go back there? Who would illume the reaches of that accursed sanctuary? Did they steal through the great doors at night and cross the bridge, not knowing what they might be disturbing?
Or has something finally opened the other gate, thought locked forever, and taken up residence in the spire, the gatehouse at the end of the world?