Biggs was slightly at fault when he expressed his opinion that the cadets\' share in the business was finished. There was a summons to attend the inquest on the four murdered seamen, a function that Derek and his companions voted a "dud stunt". However, it proved interesting, since the two survivors had recovered from their prolonged exposure, and, in spite of his wounds, one of them was able to attend the inquest.

It was a plain, unvarnished tale that he told. He described himself as mate of the s.s. Falling Star, a tramp of 250 tons, engaged in carrying general cargo to the French ports. Within twenty miles of the English coast the Falling Star was attacked by a German aeroplane—a huge machine, painted a vivid yellow, and having, in addition to the usual black crosses, a representation of an eagle holding a skull in the claws.

The mate was quite emphatic, when cross-examined by a representative of the Admiralty, that the machine was not a seaplane. It made no attempt to alight on the water, but circled round the tramp for the best part of twenty minutes before administering the coup de grace. Unarmed, the Falling Star could offer no resistance, and, as if gloating over its advantage, the Hun machine performed weird stunts above the tramp. Then, vol-planing down to within two hundred feet, the Boche dropped a heavy bomb that struck the ship fairly amidships, killing three and wounding seven members of the crew, including the whole of the engine-room staff.

The Falling Star sank rapidly, so that there was barely time to lower away the only boat that had escaped serious damage from the explosion.

Into her crowded eleven men, who, thinking that they were fortunate in getting clear of the foundering vessel, began to pull for the distant shore. Alas for a vain hope! The Hun, flying in a comparatively small circle, deliberately machine-gunned the hapless boat until, satisfying himself that the fell work was accomplished, the German airman flew off, gloating over his gallant victory over another of the strafed Englander\'s merchantmen.

"Unless I\'m very much mistaken," said Biggs, when the three cadets were on their way back to the aerodrome, "that low-down Boche is an old acquaintance. I remember back in \'17 that a \'plane marked as described was causing us a great deal of trouble. The Boche\'s name was Count Hertz von Peilfell. Our fellows were particularly anxious to bring him down. He was a bold flyer, and not at all particular as to his manners and customs. He was up to all the dirtiest tricks imaginable, and, when he wasn\'t night-bombing over our lines, was wandering across this side of the Channel. He boasted that he had taken part in three raids on London, and had sunk at least half a dozen Allied merchantmen by means of bombs. We gave him a warm reception over Dunkirk, and that was the last time he put in an appearance as far as we knew. Perhaps he was resting and recuperating his jangled nerves. However, if this blighter is Von Peilfell, I hope I\'ll meet him again, and then let the better man win."

For the next few weeks the work at Averleigh aerodrome proceeded briskly and strenuously. Somewhat to his surprise and delight, Derek Daventry was passed out after a comparatively short course, and given his commission and appointed to a home counties flying-station.

Biggs, too, was able to discard the white band round his cap, and was promptly sent across to the Somme front; but Kaye was not so fortunate. Greatly to that worthy\'s disappointment, he was put back for another course, for reasons best known to the instructors at Averleigh T.D.S.

Torringham aerodrome, to which Derek was posted, was a comparatively new station situated somewhere in Essex. It formed part of the outer aerial defences of London, and had not yet received its full establishment. Probably a marked disinclination on the part of the Boche to tempt fate amid the aerial net defences and improved anti-aircraft batteries over and around the city was responsible for the fact that there were few opportunities for the Torringham pilots to distinguish themselves. Also, the growing superiority of British and Allied airmen on the Western Front, and the reprisal raids upon the Rhine towns, kept the Hun airmen pretty much occupied, and London, in consequence, enjoyed a period of security. Nevertheless there was always the possibility of a daring Boche attempting to sneak over the metropolis under cover of darkness, and the British airmen stationed around London had to be constantly on the alert.

It was on the eighth evening following Derek\'s arrival at Torringham that the period of comparative inaction was broken. There happened to be a dance in progress, to which the officers of the depot had been invited.

"I don\'t think I\'ll take it on, old man," replied Daventry in answer to a brother officer\'s suggestion. "I\'ve quite a dozen letters to write, and I want to turn in early. Hope you\'ll have a good time."

So Derek sat in solitary state in the practically deserted ante-room while the revellers proceeded by motor to the scene of the festivities—a distance of nearly thirty miles.

"That\'s a good job done!" exclaimed Derek drowsily when the last of his correspondence was finished. "By Jove, it\'s nearly midnight! I\'ll sleep like a top to-night, unless the returning roysterers rout me out of my bed."

It seemed to the young officer as if he had not been asleep more than a couple of minutes when the electric light in his rooms was switched on and a hand grasped his shoulder.

"Turn out, you blighter!" exclaimed a voice, which Derek failed to recognize as that of the Officer of the Watch. "They\'re coming over!"

"Chuck it, old bird!" protested the still sleepy man. "If you want to rag anyone, try someone else."

"No kid," continued the O.W. "We\'ve just had a telephone message through to say that a group of Gothas passed over Harwich five minutes ago making towards London. You\'re the only pilot left on the station, so you\'ll have to go up."

Derek leapt out of bed and hurriedly threw on his clothes. He was not at all charmed with the prospect, for Torringham lay considerably off the course usually followed by the Hun raiders. To be literally hauled out of bed in the small hours of the morning, and to ascend on a pitch-dark night without any degree of certainty of being within thirty miles of a Boche airman, seemed "hardly good enough".

By the time Derek arrived at the shed in which his Dromedary biplane was kept, he felt that much of his drowsiness had passed. It was a fair night, although slightly overcast. Occasionally the stars shone through the wide rifts in the vapour. There was little or no wind.

"All ready?" he asked of the Sergeant-Mechanic.

"All ready, sir," was the reply.

By sheer force of habit Daventry tested the controls, and assured himself that the petrol-tank was filled. Then, donning his flying-kit, he clambered into his seat.

Along the electrically-lighted ground the biplane ambled, and then rose magnificently into the night air. A moment later and the powerful arc-lamps were switched off, and the countryside beneath the rapidly-climbing \'bus was shrouded in utter darkness.

At six thousand feet Derek found that his sense of lassitude had completely vanished. The bracing coldness of the rarefied atmosphere acted more effectually than the best tonic prepared by human agency. More than once he realized that he was singing at the top of his voice, as if trying to outrival the terrific roar of the powerful motors.

He was now well above the stratum of clouds. Overhead the stars shone brilliantly. He was alone, rushing through space at a speed of ninety miles an hour.

"Goodness only knows why I\'m up here," he reiterated. "Anyway, it\'s a jolly picnic. I\'ll cut out and see if anything\'s doing."

Accordingly, Daventry shut off the engine and began vol-planing as gently as possible. He listened intently for the roar of a hostile propeller above the swish of the air past struts and tension-wires.

"Thought so," he muttered, as he restarted the motor. "Nothin\' doin\'. I\'m on a dud stunt. However, I\'ll carry on."

For the best part of an hour Derek continued his flight, describing huge figures-of-eight in order to keep in touch with the aerodrome. In vain he maintained a sharp look-out for any lurid bursts of flame on the distant horizon that would indicate that the Boche was setting to work, and that the anti-aircraft guns were giving the raiders a hot tonic.

He was on the point of discharging his signal-pistol in order to inform the aerodrome that he was about to make a landing when a dark, indistinct mass shot by a hundred feet below him, and then vanished in the darkness.

"By Jove! I wonder if that\'s a Fritz?" ejaculated the young pilot. "I\'ll try and find out."

Almost before the Dromedary began to rock in the eddies in the wake of the mysterious aeroplane Derek swung his \'bus round, banking steeply ere he steadied her on her course. A glance at the altimeter showed him that the height was eight thousand five hundred feet, quite enough manoeuvring space for the work in hand, provided he could find his quarry.

It was almost like looking for a needle in a bottle of hay. Even taking into consideration the superior speed of the Dromedary, the initial start obtained by the Hun (supposing that Derek\'s surmise proved to be correct) and a slight divergence of courses would result in the two aeroplanes being separated by miles of darkness.

Still keenly on the alert, Derek held on, at the same time putting a tray of ammunition to each of the two Lewis guns, the heels of which were within a few inches of the pilot\'s face.

"I\'ve missed the beggar," declared Daventry, after continuing the phantom pursuit for nearly a quarter of an hour. "Hard lines if the fellow were a Boche. I\'ll give myself another five minutes——By smoke! now what\'s that?"

Right ahead, but on a slightly-lower level, was something gaunt, indistinct, and moving. For a few seconds Derek could hardly credit his good fortune, thinking that in the stress and strain of the night-flight he was the victim of a hallucination. Another minute, however, removed all cause for doubt. It was a \'plane; more, it was a Boche, for the black crosses of infamy were discernible in the cold starlight.

The Dromedary was rocking in the tail-stream of the Hun machine. Gently Derek brought his \'bus up, until it was flying in comparatively still air. Eighty yards away was the Boche, flying serenely in blissful ignorance of the fact that a British machine was literally sitting on its tail.

Deliberately, and without the faintest compunction—for the night-raider had none when dropping his powerful bombs upon the civilian population of London and other cities and towns—Derek brought the sights of the right-hand gun to bear upon the back of the Hun pilot. A burst of vivid flashes, and the deed was done.

The German machine dipped abruptly, and dropped into a spinning nose-dive, while a long trail of reddish flames, terminating in a cloud of fire-tinged smoke, told its own tale. The petrol-tank had taken fire, and the doom of the raider was sealed. No amount of trickery would avail. It was impossible for Fritz to attempt his now well-known spin in the hope of deluding his antagonist, and then, by flattening out, get clear away. The fire had "put the hat" on that, even if the pilot had not been killed outright by the hail of Lewis-gun bullets.

"May as well see what happens," soliloquised Daventry. "So here goes!"

Diving almost vertically, he followed the visible track of the crashing Hun. With his feet braced firmly against the rudder-bar, and his head and shoulders well back, Derek maintained the plunge, ready at the first inkling of danger to either loop or flatten out. In spite of the terrific pace, the flaring debris of the vanquished Gotha was falling even faster, followed by a galaxy of falling embers.

Suddenly a blinding flash seemed to leap out of the darkness within a few yards of the diving Dromedary. Another and another followed in quick succession, and although the noise was drowned by the roar of the engine, Derek guessed instantly and rightly.

"Shrapnel, by smoke!" he exclaimed. "I\'m being strafed by our own antis."

With a sudden jerk that would have spelt disaster had any of the struts and tension-wires been of faulty workmanship, the Dromedary checked her downward plunge in order to avoid the unpleasant attentions of "Archibald", while for the first time Derek became aware that he was in the concentrated and direct glare of half a dozen powerful searchlights.

"Why on earth can\'t the idiots see my distinguishing marks!" exclaimed Derek petulantly, forgetting that when a machine is diving steeply the planes present to an observer on the ground the appearance of two parallel lines. He groped for his Very\'s pistol in order to give the customary signal to show that it was a British aeroplane that was the object of the anti-aircraft gunners\' attention, but in the steep nose-dive that important article had slid from its appointed place.

Rocking and pitching in the rudely-disturbed air, the Dromedary dodged and twisted, vainly attempting to elude the beams of the searchlights. Then, with a most disconcerting crash, a couple of struts were shattered like matchwood, and the next instant the \'bus, badly out of control, began to drop through the intervening thousand feet that separated her from the ground.

Derek prepared for a crash; sliding as far as possible under the cambered deck of the fuselage, he waited for the inevitable. The biplane on crashing would almost certainly land on her nose and turn completely over. It was possible to survive the impact, but the greatest danger lay in the possibility of the luckless pilot being hurled against the knife-like tension-wires, or having his head battered against the heels of the two machine-guns.

To Derek the biplane appeared to be dropping slowly, although actually very few seconds elapsed before the crash came. The anti-aircraft guns had ceased firing, either because the gunners knew that they had scored a hit, or else the altitude was too small to admit of the guns being fired without risk of doing great damage to the adjacent village. The concerted rays of the searchlights, however, continued to play upon the falling machine, until an intervening ridge masked them. There was a sudden transition from dazzling light to utter darkness—Derek realized that he was now but a few feet from the ground.

Crash!

As he expected, the machine struck nose first. The quivering fabric of the fuselage was suddenly checked, the change of direction causing Derek\'s knees to bend and hit hard against the deck. A blow like that of a gigantic sledge-hammer seemed to smite him betwixt the shoulder-blades.

Then, rearing, the fuselage toppled completely over, and the next instant Derek found himself being dragged down through icy-cold water.