'The Great Submarine Plot'
Written by
William Le Queux
Copyright 1917
4th adventure in the collection .
Oscar Engström is a Swedish engineer whose activities have intrigued Gerry Sant for some weeks and now in Switzerland, he hopes to learn what the man is really up to and how might it help the German war effort.
It is told in four chapters entitled:
The Great Submarine Plot
The Real Mr. Engström
In a Tight Corner
The Plot Revealed