RICHARD DUVALL, waiting with nervous impatience in the closet in FranÇois' room, at last heard a soft and guarded step upon the stairs. He drew back, his muscles tense, and gazed fixedly at the door.

Although the room was dark, the glow of the street lamps from without, the faint light of the evening sky, sufficed, now that his eyes had become accustomed to the darkness, to enable him not only to recognize the chauffeur as he entered the room, but to follow his movements with little or no difficulty.

The man seemed hurried. He groped his way to the dresser at the opposite side of the room, and felt about for the searchlight which Duvall knew lay within easy reach.

Having secured it, he directed it for a brief moment upon his watch, noted the time, then, going to the door, opened it, and began to listen intently.The detective at once surmised that he was listening for the departure of his confederate, the man with the black beard.

Presently the chauffeur drew back, closing the door with a grunt of satisfaction, and once more approached the dresser. Duvall concluded that he had gone to get the colored glasses by which he would be able to make the required signals.

In a moment he returned to the window, and Duvall saw him place the two glass cups upon the sill, and lean out expectantly.

It seemed a long time before he stirred. The detective, looking over his shoulder, found that his line of vision was interrupted so that he could not see the lights which flashed past the entrance of the Avenue Malakoff. He was forced to content himself with keeping a close watch upon the chauffeur.

Suddenly the man, by an almost instantaneous movement, clapped one of the little glass cups over the end of the tube which formed the searchlight, and directed it toward the street. Duvall could not tell whether the signal was blue, or red. He had every reason to believe, however, that it was the former.

The chauffeur held the tube upon the window sill for a few seconds only, then withdrew it, and started to cross the room toward the south window. As he did so, he swept the light into the room, and for an instant it fell upon the crack in the closet door through which Duvall was peering. He was conscious of a blinding blue radiance, close to his eyes, and the sudden flash caused him to draw back with a quick and involuntary movement. He realized that the chauffeur had not seen him, and that, in a few moments more, the signal would be given which would bring untold happiness to both Mr. Stapleton and his wife.

The momentary recoil, however, was fatal to his plans. Although he moved his head but a fraction of an inch, the suddenness of the movement was sufficient to cause a metal coat hanger, which hung, empty, from a hook, to click sharply against its neighbor.

The chauffeur spun around with the quickness of a cat, and, grasping the knob of the closet door, threw it open. In his hand he still clutched the tube of the searchlight.

Duvall at the same moment reached for the revolver which lay in a side pocket of his coat. He realized instantly that, now that his presence had been discovered, the chauffeur would of course not send the signal to his confederates in Passy which would result in the telephoning of the address to Mr. Stapleton, but would on the contrary flash a red signal, which the detective fully believed would result in the child's death.

It was imperative that this should be prevented. Duvall had determined to be present in the chauffeur's room for two reasons,—first, to send the favorable signal to Passy himself, should things go wrong, and the chauffeur receive a red flash from the street; secondly, to arrest FranÇois in the act of receiving and sending the signals.

He now realized that he must do both, and that, too, without a moment's delay.

As the chauffeur threw open the door he flashed the blue light full upon the crouching figure of the detective.

The latter, revolver in hand, commanded him sharply to throw up his hands.

The chauffeur did so—thereby directing the light of the electric lamp toward the ceiling. The sudden change from the glare which an instant before had been in his eyes, to almost total darkness, left Duvall momentarily blind. His eyes could not instantaneously respond to the withdrawal of the light. The figure of the chauffeur appeared but a dark and formless shadow.

The latter, however, not having faced the glare of the light, was able to see without difficulty. With lightning like quickness he spun around on one foot, until his back instead of his face was toward the detective. Then his right foot rose, in the famous and deadly blow of the savate.

It has been said that this backward kick, so dear to the heart of the Parisian crook, is more to be feared than any possible onslaught in good old Anglo-Saxon style with the fists. Certainly in this instance it was too much for Richard Duvall. The unexpected blow, coming during the moment when the sudden darkness had left him blinded and confused, sent him crashing back into the depths of the closet, buried beneath a mass of clothing. His arms, entangled in falling coats and waistcoats, were helpless. The revolver flew from his hand, and lay useless on the floor.

The chauffeur went about his business calmly. His first move was to direct the searchlight carefully into the interior of the closet, slipping the blue cup from the end of it as he did so and allowing it to fall unheeded to the floor. His second was to draw a long and peculiarly deadly looking knife.

His quick eye saw at once that the revolver was no longer in the detective's grasp. His searchlight enabled him to discern it, lying on the floor to one side of the closet. Before Duvall could extricate himself from the articles of clothing in which he was entangled, FranÇois had stooped quickly, picked up the revolver, and slammed the door of the closet upon him. As he struggled to his feet, the detective heard the click of the key as it turned in the lock. He was a prisoner.

Without losing a moment, the chauffeur tossed the revolver upon the table, took up the cup-shaped bit of red glass, fitted it to the tube of the searchlight, and, going to the south window, placed it upon the sill in such a way that its crimson glare was directed almost due south. It was evident that the position in which the light was placed was marked by the two tiny scratches cut in the woodwork of the window sill. In a moment he had turned back toward the closet door.

Duvall, meanwhile, realized that only by instant and superhuman effort could he hope to remedy the frightful situation which his unlucky movement had precipitated.

He braced his shoulders and back against the rear wall of the closet, put his two feet against the door, and with every atom of strength in his body strove to force it open.

His movements had been quick. Just as the chauffeur turned back from the window toward the room, Duvall, his muscles knotted with effort, drove the full force of his body against the closet door.

The lock, a cheap affair, was torn loose in a twinkling, and an instant later the two men had grappled in the center of the room.

The detective's one desire was to get to the window, remove the red light which he knew was flashing its fateful message across the housetops, and substitute for it a blue light, which he hoped even now might shine forth in time to redeem the situation.

This, however, the chauffeur was equally determined to prevent. He realized that he was caught, that his complicity in the affair was known, and that he must warn his comrades of his danger, so that, by refusing to give up the boy, they might effect his release. He was fighting for his liberty as desperately as Duvall was fighting for that of Mr. Stapleton's child.

The two men were evenly matched. The chauffeur was perhaps the stronger, in shoulders and arms, due to his profession. The constant grip upon the steering wheel had given to his upper body muscles like steel.

The detective, though somewhat less powerful in this direction, was stronger in the back and legs. He had been an athlete, at college, and his recent life upon the farm at home had toughened and hardened him from head to foot.

He rushed at his opponent, threw his arms around the latter's waist, and strove to lift him and throw him to the floor.

The chauffeur at the same time got his right arm about Duvall's throat, and with his left did his best to gouge out one of the latter's eyes. His was the style of fighting that considers not means, but results.

For a moment they swayed heavily about the room, the detective burying his face in his opponent's side to protect his eyes, and at the same time striving with all his might to force him back toward the bed.

FranÇois, however, fought well. He began to compress his adversary's throat in a choking grip of wrist and forearm which threatened to put an end to the struggle in short order. At the same time his left thumb continually sought the detective's eyes.

Suddenly it reached one of them. Duvall felt a blinding sense of pain as the thumb nail sank into the soft and tender muscles about the eye. The shock was fatal to the plans of the chauffeur; for it raised up in his opponent a great and deadly rage, that for an instant gave him the strength of a madman. He raised his opponent from the floor as though the latter had been a child, broke the grip upon his throat by straightening his head, and with a mighty heave hurled him to the floor.

The fellow struck upon his side, his temple crashing loudly against the wooden floor. Duvall stood over him for an instant, breathing heavily, convulsively, then turned and snatched the searchlight from the window sill and threw it upon the bed.

There was a trunk against the wall of the room, near the window, and about it a broad leather strap. Duvall tore the strap from its place, and in a few moments had fastened it about the chauffeur's arms and body.A towel, knotted about his ankles, rendered him helpless. Then the detective began to search upon the floor for the bit of blue glass.

In his heart there was no joy at the victory he had just won. He had captured one of the kidnappers, it was true; but on the other hand he had, by his own carelessness, prevented the safe return of the kidnapped boy to his parents.

He pictured the father and mother, patiently waiting below for the telephone message which would never come, and wondered how he would dare to tell them the truth.

At last his nervous fingers closed upon the little glass cup, where it had rolled under the edge of the dresser when FranÇois had thrown it down. Trembling with haste, he fixed it to the searchlight which he took from the bed, and, with a hopeless feeling, approached the window, and began to wave the light frantically in the direction of Passy.

For several moments there was no response. As a matter of fact, he scarcely expected any. Then all of a sudden he saw a faint red gleam, like a star, flash from the distant night, and then go out.

He stood, helpless, waiting for it to reappear, hardly daring to hope that it would do so. Suddenly it shone again, this time for a longer period, and then disappeared. He wondered what it meant, and was scarcely surprised when the light again flashed, this time making five quick flashes, which he instantly recognized as Morse code for the letter "P." There was a brief interval, then once more the signals began to flash. This time he read them without difficulty. There were four letters, spelling the word "Help."

For an instant he leveled the tube of the searchlight toward the point from which the flashes came, guiding it by the scratches on the sill, and began pressing the button which turned the light on and off. "Where are you?" he spelled out, then waited fearfully for the reply. He dared send no other message. The person at the other end, the one who sent this ominous word, "help," must be one of the kidnappers; yet why should he signal for assistance? He could make nothing of the matter, but he reasoned that anyone calling for help would be sure to give their location, otherwise how could they expect to receive it.

For a moment the red flashes began again, and this time he began to get the numbers. There were four quick flashes and a long dash, then others in rapid succession: "4-2-R-u-e-N-i-c-o-l-o, P-a-s-s-y," the message read. "C-o-m-e q-u-i-c-k."

Duvall's head reeled, as he spelled out the words. He had not realized until now that he was wounded. The blood, pouring down his face from the great gash in his cheek, spattered thickly upon the window sill. He turned from the window, then realized that he must send some answer, to let this mysterious person at the other end of the line know that his message had been safely received.

"Will come at once. Who are you?" he spelled out, laboriously, his head spinning, his fingers trembling from weakness as he tried to stop the flow of blood from his wound.

"G-R-A-C-E D-U-V-A-L-L" came back the flashes, quick, clear cut, unmistakable.

Duvall dropped the searchlight to the floor with a harsh laugh. His brain was reeling—the whole thing became a foolish, senseless nightmare. He wondered if he was delirious, and had dreamed it all. Again he flashed a signal into the darkness. "Who are you?" he spelled out again. He did not believe that he had read the former answer aright. Evidently his imagination was playing him tricks—Grace had been on his mind so constantly, throughout the day. He wiped the blood from his eyes and stared eagerly out into the darkness. There was no response.

Then he remembered the words of the message, "Come quick." There was no time for idle speculations as to the identity of the person who had sent him the message.

He rushed to the stairs, and with tottering footsteps descended to the library below. FranÇois, the chauffeur, still lay, bound and unconscious, upon the floor.