Archie takes the job hoping to find redemption following a scandalous love affair that left him a broken man and a drunkard, and soon finds himself immersed in the picturesque village of Bennachie playing the not-too-far-off role of a recovering invalid. Archie tries to uncover the identity of the Singing Spider-—an Italian spy and master of disguise thought to be behind D7's murder—-with the help of an American Professor, a local rogue who's also seeking redemption, and a lovely young minister's daughter. But first Archie has to find out how the Singing Spider is tied to a puzzling phrase that translates as "The Pit of Baal" and the mysterious red lights at the Bennachie stone, an artifact the Professor believes dates back to the ancient Phoenicians.
It's definitely a novel of its time, thematically and stylistically, but there's a good rendering of the Scottish setting that was so similiar to areas MacVicar knew well, and to its characters. There's also a bit of naive sweetness to it that you don't often find in spy-themed suspense novels, no doubt a nod to the author's Presbyterian roots and his young-adult writings. It's definitely a G- or PG+ type of plot. The Singing Spider was made into a radio program for BBC Scotland in 1950, although I doubt any traces of it exist. As a matter of fact, there is very little about the author of this book on the Web, and unless you can find his works at your local library, you may find it difficult to get your hands on them.