Publisher's Synopsis
Harry Barnett is in England following the death of his mother. Whilst settling her affairs he meets two old acquaintances from his National Service days in the RAF. A lavish reunion has been organized to mark their fiftieth anniversary at the Scottish castle where they spent three months acting as guinea pigs in a psychological experiment. But en route to Aberdeen, they are rudely interrupted by the apparent suicide of one of their number. Later at the castle another of the old comrades dies in suspicious circumstances. The dark turn the weekend has taken suddenly becomes inky black, and Harry finds himself plunged into a struggle for their very survival.
