When we drove into the grounds of the Darwin home at five o'clock that night, McKelvie ordered me to hide my car behind the garage and then to join him in the passageway. As I obeyed I saw him helping Lee, with Cora's aid, to mount the steps to the back door, for he wanted the two of them for purposes of identification, since both had been victims of the unprincipled man we had come there to-night to try to trap.

I parked my car where it could not be seen by anyone approaching the house and then returned to the servants' wing and entered the passageway, where McKelvie was disposing of his forces. The three burly policemen that Jones had brought with him McKelvie ordered to remain where they were until it grew dark, when they were to hide themselves in the grounds, toward the side of the house. When they saw a light in the study they were then to group themselves around the door to the secret entrance, which he had already pointed out to one of their number while I was parking my car. If anyone came out through this door they were to arrest that person, and under no circumstances to let him get away, even if they had to shoot him. The men saluted and I could see by the determination written on their faces that the criminal would have small chance of escaping their vigilance.

Then McKelvie opened the door into the main wing and asked Cora and Lee to remain in Orton's workroom until they were needed.

"And under no circumstances show a light of any kind," he added. They did not need to promise, for they preferred a darkened room in which to tell each other the sweet nothings that lovers are fond of murmuring, and I envied them their happiness as I thought of Ruth shut away where even my loving care could not reach her.

In the fading daylight the study was dim, but we managed to make out the outlines of the furniture, and so were able to move about without turning on the lamp. McKelvie grouped some chairs around the table and told us to seat ourselves, since at that distance we could not be seen by the criminal as he stepped from the safe. Then McKelvie arranged the shades, drawing them so that they did not quite reach the bottom of the windows, thus allowing the light to gleam through later, as a signal to the waiting policemen.

When everything was ready McKelvie spoke to us in an undertone. "I do not know how long we shall have to wait for him. He will come when it is dark, perhaps, and again he may not turn up until midnight. In any event, whether our vigil be long or short, I want to impress upon you the necessity for absolute silence. A false move and we may lose every advantage and the criminal as well."

We declared ourselves ready to obey his instructions, however long we might have to wait, and he crossed the room and took up his position beside the safe door with the metal handcuffs in his hand, prepared to snap them on the wrists of the man who should come forth from the entrance.

I glanced at Jones and Grenville and saw to my amusement that the police detective was sound asleep. He reminded me of a watchdog that though he might doze would yet be instantly on the alert at the least hint of danger. The District Attorney caught my look and smiled, then he leaned back in his chair and set himself to wait with what patience he might possess.

I turned to my thoughts, thankful that McKelvie had spared Mr. Trenton this ordeal, for now that Cunningham was exonerated, the burden of the crime must fall upon Dick, who, after all, was the only one well enough acquainted with circumstances to have attempted the schemes which McKelvie had foiled. Yet it seemed such a mad thing to do, to put his head in the noose a second time when he had just been cleared of his first crime, unless James Gilmore's story was all of a piece with the other deceptions Dick had practised upon us. Who was Gilmore any way? Had we any proof that his story was true? He may have been paid to put us off the scent by making us believe that Dick could not commit another crime since he was innocent of the first one. But, again, there was McKelvie's statement that with the exception of the Chinamen and those two ruffians, the criminal had steered clear of confederates. I could not divine Dick's motive for the deed, since the murder was not and never had been, one of impulse.

I wished heartily that the whole thing was over and this suspense ended, yet when the lamp suddenly lighted on the table and I knew that the hour was at hand, since it must have been the criminal's hand that had pressed the switch in the safe, I closed my eyes. I did not want to see the door swing open and Dick step out of that safe.

I heard a metallic click as McKelvie snapped on the handcuffs, and I opened my eyes with a start as I realized by the snarl of rage that had come from the murderer's lips that we had caught the man as neatly as one traps a wild and dangerous animal.

McKelvie laughed as he slammed the door of the safe, and the three of us rose precipitately (Jones had wakened when the lamp went on), for we could make out the criminal's figure as he came rapidly toward us. When he stood within the circle of light, confronting the muzzle of Jones' gun, I looked into his face, then I gasped audibly.

The man before me was not Dick, but the lawyer—Cunningham!

"This is an outrage!" he exclaimed furiously. "What do you mean by putting such an indignity upon me?" and he glared at McKelvie.

McKelvie smiled in an exasperating manner. "I was expecting the criminal to come through that entrance, since he alone possesses a key to it. I saw a man appear and clapped on the bracelets. It happened to be you. How do you explain the circumstance?" he inquired politely.

"Very easily," retorted Cunningham coolly, recovering his poise, "I was going over a lot of old papers and came across a sealed envelope addressed to me in Darwin's hand. Wondering what it could portend I opened it. Inside I found a small key and the explanation of the secret of the entrance. Darwin also went on to say that he was taking me into his confidence in case anything should ever happen to him. Having a fondness for amateur detective work, like yourself, Mr. McKelvie," here he bowed ironically to McKelvie, "I decided to use the opportunity which fate had bestowed upon me to do a little investigating on my own account."

"Very ingenious, but it won't do," returned McKelvie, adding with a sarcastic inflection, "I suppose he also told you the six-letter combination that I used to lock the safe—after he was dead?"

Cunningham flushed and bit his lip, but before he could think of an appropriate retort, McKelvie had turned to Jones.

"You won't need to use that gun, Jones," he said with a twinkle. "Our prisoner is too valuable to shoot—as yet. Call in the others, please, and light the room as you pass the switch."

Jones pocketed his gun, and departed on his errand, lighting the study, as we had agreed to do, for the guidance of the men outside. In a second he was back again with Lee and Cora. As Cunningham's eyes rested on the girl, who had her arm around Lee and was helping him tenderly to a chair, the man's face darkened and his eyes blazed upon her.

"Miss Manning, have you ever seen this man before?" asked McKelvie when Lee was seated and Cora had turned toward us.

The girl looked Cunningham up and down, from the sole of his patent leather shoes to the crown of his gray-streaked red hair, then she shook her head and answered simply, "No, Mr. McKelvie, I have never seen him before."

"Now I trust that you are satisfied?" demanded Cunningham, insolently, a gleam of triumph in his eyes. "You will oblige me by removing these things."

Though he held out his manacled hands to McKelvie, his eyes remained on Cora's face with a look impossible to mistake. The man was in love with her, though how that was possible when she did not know him, I was at a loss to decide. McKelvie took a step forward and I thought he was going to comply with Cunningham's request, but he made no move to release his prisoner.

"Sorry to have to refuse a gentleman of your standing, but you are far safer to me with the bracelets on," returned McKelvie imperturbably. "You are undoubtedly clever or you could not have evaded me so long, but the trouble with you, as it is with all clever criminals, is that you are egotistical. You commit a crime and get away with it and then you immediately think yourself a genius, so much more wonderful than your fellows who have paid the penalty for their deeds, so infinitely superior to the police and the detectives that you have no fear of being caught. But like all your class, there is a weak joint in your armor. There is no such thing as an infallible criminal and a perfect crime. You may get away once, or perhaps a score of times, but in the end your weakness trips you and you fall into the hands of the authorities. In your case the thing that tripped you and delivered you to us was—love for a woman. A dangerous game to play, the woman game, Mr. Cunningham, but love knows no reason. You were so desperately infatuated with Cora Manning that the thought of going away and leaving her to a more successful rival was agony to you, and so you remained to persuade her to go with you. That is why you are here now, facing arrest under an accusation of murder."

In wondering silence we listened to McKelvie's words and Cora said quickly, "In love with me? But I never saw him before."

Cunningham only smiled coolly. "You have no proof, my dear sir, no proof at all."

"Haven't I? I am not as amateurish as I look," said McKelvie, dryly. Then he faced the man before him squarely and addressed him in a tone of grim earnestness from which all hint of banter had fled. "You demand proofs. I will give them to you. I know why the murder was committed, why Mrs. Darwin was implicated, because I know exactly what took place in this room on the night of October seventh, from the moment when Richard Trenton stepped through that French window to the moment when the murderer left the room by the secret entrance. In other words, the game is up—Mr. Philip Darwin!" and McKelvie's hand shot out toward his prisoner's face.

I heard Lee's wondering, "Uncle Phil?" and unable to believe my ears I took a second look. Then, "Good God!" I cried, for the red hair and beard were gone and the man standing where Cunningham had been was indeed Ruth's husband, for whose murder she was even now enduring the horrors of prison life, Philip Darwin, but Philip Darwin without his eyeglasses and without his beard!

Who, then, was the man we had found dead in this room, the man we had buried under Darwin's name? A sudden conviction borne of McKelvie's last words flashed across my mind.

"Was it—?" I began.

"Yes," replied McKelvie, "the man who was so foully murdered in this room that night was—Richard Trenton!"

Cora cried cut, "Dick, oh, not Dick!" and I put my hand to my head, for my brain was in a whirl. Yet I was conscious of a feeling of thankfulness that he was the victim rather than the perpetrator of the crime.

With a snarl of rage Darwin broke from McKelvie's hand and fled toward the safe. Jones started to follow, but McKelvie checked him with a laugh.

"Let him go, Jones. Have you forgotten that there are three men guarding the outer door?" he said.

Darwin paused abruptly and turned a hate-distorted face toward us, then he recovered his cool manner and walked back calmly to where we stood.

"You win," he said to McKelvie with a shrug. "What do you want of me?"

"If you will kindly be seated I should like to explain, with your corroboration, just exactly what did take place in this room that night," answered McKelvie.

"No," returned Darwin, "let me tell the story, for you would bungle the tale. I'll accept your word that you know what happened, since otherwise you could not have unmasked me. Kindly take off those bracelets, they annoy me, and give me a cigar. I swear to you that I shall make no attempt to leave this room."

For a long minute the two men looked into one another's eyes, then McKelvie stepped forward and removed the handcuffs. He bestowed them in his pocket, took out a cigar, and offered it to Darwin.

The man accepted the cigar with a bow, lighted it, and then drawing a chair into the center of the circle which we had formed, he leaned back nonchalantly and began his tale.