This follows close on the heels of The Mystery of the Ruined Abbey and takes Rick Davis through another summer's adventure in Scotland where his father has been sent from the U.S. on a Government research job. With his friends Gavin and Sheila Cameron of the small town of Inverfoyle, Rick stumbles on another mystery to keep him occupied. The boys find some Swiss coins in the hills. The coins are the first of a chain of clues that lead to the uncovering of a countryman's plot to overthrow the British government. Readable repartee and derring do, but it nevertheless simmers down to recognizable and undisturbing characters and situations.