"Two thefts inside ten days...do you think can be any connection?" A quiet Cornish village and its law abiding community are rocked by a series of strange events in the summer of 1943. While on a standard Home Guard training manoeuvre, Arthur Wedgewood discovers that supplies of explosives are missing from his stores. When the local police fail to take the necessary steps, Inspector French takes charge to untangle the threads of the crime perpetrated by an Enemy Unseen...