I am looking for a book which was a variation of Arthurian legends. I have read it in Polish around 10 years ago, but I'm quite sure book was translated (probably from English).
The story was set up in the medieval times. The main clue I remember is a cave with some sort of futuristic equipment and silos capable of hibernating(?) people. I think book started when Merlin woke from his long sleep to fulfill his quest of guiding Arthur (it may be that Merlin woke Arthur from the silo, but I am certain about someone waking up). Then Arthur goes on his quest and at some point meets Morgan. I recollect her playing some mind tricks on Arthur and this part was vague, but I can't say if it is due to my hollow memory, lack of understanding of written words, or indeed vagueness.
I know it's not much, but I've seen some impressive identifications here, so I have hope.
I have checked this list, but did not find any description mentioning fantasy setting with sci-fi elements.