From old pro Gilbert, an eventful eve-of-WW I outing for MO5 operative Luke Pagan and his roguish sidekick Joe Narrabone (Ring of Terror, 1995, etc.). Posted to Portsmouth early in 1914 to keep an eye out for potential enemies, Luke and Joe determine (their pre-satellite vantage point is a conveniently sited tree) that a crafty German spy named Erich Krieger, from a coastal estate rented under false pretenses, supplies overflying zeppelins with intelligence on Royal Navy movements. By the time civil authorities can be prodded into action, however, the Kaiser's man has slipped back to Europe by U-boat. With the guns of August by then in full roar, Luke and Joe turn their attention to counterespionage. After rounding up a troublesome group of sleeper agents who, directed by Krieger, have been sabotaging fleet vessels and threatening to disrupt the vital flow of munitions to the front, the resourceful partners, in the spring of 1915, go after the cabars mastermind. Overcoming treachery, the military's inertia, attempts on their lives, and other misfortunes, Luke and Joe eventually trap their quarry in the chalk caverns that underlie a behind-the-lines staging area in Le Touquet, France. A lively period piece that affords a welcome change of pace from the high-tech exertions of recent crops of pre-millennial secret agents.