In this camp were none but the suicidally brave type of fighters, and it was only that kind fit to essay the trackless line of three hundred miles over the sea. From what the boys, or, rather one of them, Henri, could learn from the camp talk, a pair of the latest Zeppelin dirigibles were to participate, but the main movers of this attack were evidently to be airships of the small, non-rigid Parseval build, for bomb work. The truth of the matter was, the young aviators, at the order of Roque, were so taken up with the tuning of a seaplane just before the fleet went aloft that they could not have listed the starters with any degree of accuracy. They only knew positively that they were going aloft, and their own machine would require their individual attention. About 8:30 that night the glare of a powerful searchlight from one of the German airships directed its rays over the heart of the English city of Yarmouth. Two bombs dropped almost simultaneously. The boys saw the city below suddenly plunged into darkness. Five more bombs were hurled from the sky. The fleet then swiftly moved northeast, and more bombs crashed into the town of Kings Lynn. Roque had assumed no active part as a leader in the deadly maneuvers--his was a thinking assignment. It was midnight when the fleet turned eastward and fled back across the North Sea. "It might have been London," muttered the secret agent, "if the game could have been played without a break." Preparations to repel just such an invasion had been made in the great city. Ardelle must have gotten his warning across, but the coast towns failed to heed it. The Roque machine kept its speed when the balance of the fleet checked flight at Amesland. The secret agent was bound for Cuxhaven, doubtless to plan another tiger spring at the foe. He was all for air campaigning these days. "You will witness the sight of your lives, you young cyclones, before last night's mist of the North Sea dries in your hair." This significant remark on Cuxhaven docks set the boys in the highest state of expectancy. It was seldom that Roque billed anything ahead of time, and surely something extraordinary must be in the wind. Three days later, from a dizzy height, they witnessed a sky battle without parallel in military annals, and which dimmed the memory of any of their previous remarkable experiences in the war zone. The French coast town of Dunkirk, to which the boys had on a happy day gone by been delivered by submarine and taken away in a seaplane, was the ground center of this spectacular conquest of the air--the first of its kind in the history of the world. Twenty hours earlier a fleet of British seaplanes had bombarded the Belgian port of Zeebrugge, held by the Germans, news of which had soon after reached the mystery man, Roque, by way of one of the innumerable channels of communication with which he kept himself constantly in touch.