The Keep by Roger Taylor

Isolated and deep in the mountains, the Keep is a disturbing place. Why would the New Order want it, and for what? But you didn’t ask questions the way things were. You kept your head down and did as you were told. Just do your job, Josyff kept reminding himself.

Yet there were strange problems with his work... and dreams... and him... and the building itself -- massive, yet, somehow, changing.

And when the authoritarian Adroyan arrived at the Keep, together with his nemesis, Esyal, things become even stranger, pushing Josyff to the edge of his sanity...