G. C. Clewett – Blood Dynasty (New English Library, March 1973)
“The girl was secretive. Altson didn’t mind for he had secrets of his own. Like the knife he carried and what he did with it
She was strangely attractive, and that should have given him a clue. The long black flowing hair, the thick dark glasses, the skin as pale as death….
It was later when he realised. When he’d come into the dim, grey room and seen the faces of his captors. The girl had told him of the place called Morne but now it was to late. At the centre of the nightmare web , he was fighting for his life against the Dark Power of Alien Evil.”
Thanks to Killercrab for providing the scan and blurb!