The House on the Old Cliffs

An imaginative mystery to be solved, which Adrian Tchaikovsky, a master of the unexpected, manages to entice and string you along, until you don't want, but need to know the answers.
Pseudo-historian Doctor Hendry is missing. His employers want answers.
Paranormal investigators Michael and Walter join the search party to Hendry's remote Scottish cliff-top home, accompanied by two unscrupulous mercenaries and a deeply sceptical history professor.
Among the doctor's research they find more than they bargained for or can even comprehend, and the rescue becomes a fight for survival.