It was unbroken and I hastily ran to pick it up. By its light I could see Pons struggling with an astonishing creature that alternately glowed with unearthly blue light and then as rapidly disappeared as they rolled over. I ran to help him but my companion was already ripping the hideous mask from the creature. The disheveled, almost pitiful face of a young man was revealed. He had been standing flat against the wall, made invisible by the black material he wore.
"Allow me to present Mr. Norman Knight, our fellow guest from The Harrow Inn. Better known hereabouts as the crawling horror of Grimstone Marsh!"
11
Pons chuckled grimly, looking down at the baffled figure on the ground.
"You seem to have recovered from your limp in an admirably short time, Mr. Knight."
I stared at the strange tableau in bewilderment.
"I do not understand any of this, Pons."
My companion held up his hand.
"All will be made clear in a very few moments, Parker."
He crossed to the fallen man and helped him up on to the wooden box where he slumped, an abject and dejected figure, his head in his hands.
"As you can see, Parker, an ingenious though simple stratagem. The figure of the marsh phantom is painted with the phosphorescent solution on the front only. By simply turning away from the viewer, Mr. Knight could render himself to all intents and purposes invisible on a dark night."
I could not repress a gasp.
"So that was the answer, Pons!"
My companion nodded.
"On the occasions when the phantom suddenly disappeared, he was simply standing still in the center of the marsh, keeping his back turned. As soon as he heard his victim move away he slipped off this hooded garment, returned to this shed and secreted the evidence of his wicked charade."
"But what was the point of all this, Pons?"
"You may well ask, Dr. Parker," said young Knight, suddenly standing up and turning a white but composed face to us. "My masquerade may not be as wicked as you think. Rather regard it in the light of an angel with a flaming sword.come to right a great wrong."
"I am not denying your motives," said Solar Pons, with a strange smile, "but you were very mistaken in adopting this particular method to achieve your ends."
We were interrupted at this moment in a highly dramatic fashion.
We had been so absorbed in the drama before us that we had not noticed a faint shadow creeping closer from the door of the shed. Now a figure materialized in the faint beam of Pons' torch. Silas Grimstone's face was distorted with pain and anger and it was with a shock that I saw my pistol clutched in his trembling hands. Pons shot me a reproachful glance but his voice was firm and steady as be turned toward the old man.
"What does this mean, Mr. Grimstone?"
Grimstone stared at us with an ashen countenance; it was obvious his glazed eyes saw nothing but the form of young Knight. His voice, when it came, was thick.
"So, you have come back from the marsh, have you? Well, I put you there once and I can do so again!"
He raised the revolver with a hoarse cry but Pons' reaction was as quick as a striking snake's. He cannoned into Knight and the crack of the explosion and the tinkle of window glass that followed showed where the bullet had gone.
"Run for your life!" Solar Pons commanded.
He extinguished the torch and I just caught a glimpse of Knight against the lighter square of the doorway before he had gone. There was another shot and then old Grimstone rushed after him at a lurching run.
"I am sorry, Pons," I said, as the lean shadow of my friend got to its feet.
Pons switched on his light again and as he did so we heard the faint crack of an explosion outside.
"No time for recriminations, Parker. Pray that we shall be able to avoid another tragedy."
Outside, we found the mist thickening a little but it was not difficult to see the direction our quarry had taken. Knight had wisely gone down into the swamp area, where he was obviously at home, instead of across the uplands where he would have made an excellent target.
But the way soon twisted among thick bushes and Pons twice stopped to examine broken reed-stems under his light. His face bore the stamp of great anxiety.
"He has turned aside from the path, Parker. I fear the worst."
A few seconds later we came upon my revolver where it had fallen barrel down among the reeds. I bent to pick it up and found Pons' hand on my arm.
"It would be unwise to venture farther, Parker."
As he spoke there came an unearthly scream from the misty depths of the marsh ahead. It had such fear and horror in it that I think I shall remember it to my dying day and even Pons seemed shaken. We stood there as it echoed and reechoed until it finally died away.
"It is all my fault," I said. "After all your efforts on behalf of your client."
Pons shook his head, a strange expression on his features in the glow of the flashlight. He led the way back to the firmer footing of the path.
"Client or no, Parker, I think the world has seen the last of a damnable villain. If he has not been scared into permanent flight, young Knight is the only person who can fill in the missing pieces for us."
I put the revolver back into my pocket; as we stepped up on to the higher ground there was a low rustling in the bushes.
The disheveled figure of Knight stepped out onto the path, an obviously shaken and frightened man. "I swear I did not mean it to end like this, Mr. Pons," he said wildly.
Solar Pons looked at him for a long moment.
"Explanations will keep, Mr. Knight," he said slowly. "I suggest we return to the manor immediately and break the news to Miss Grimstone."
12
"I am deeply shocked, but I cannot say I am entirely surprised at this ending, Mr. Pons."
Miss Sylvia Grimstone's face was gray and strained but she was quite in command of herself as she sat by the fire in the parlor at Grimstone Manor and poured thick, hot coffee.
I took the cup from her gratefully, for I was frozen to the bone and the fire in the grate had sunk to a few glowing embers. Knight sat at a round table near the fire, midway between myself and Pons and our hostess.
"The police will be here within the hour, Miss Grimstone," said Solar Pons, his restless eyes probing round the room. "I think some explanations are in order before they arrive."
"I would be grateful for some light in this business, Pons, for I am completely in the dark."
My companion smiled wryly as he put down his cup and looked across at the young man who sat, pale and trembling before us.
"As I have said on more than one occasion, Parker, patience is not always your strong suit. However, let me get briefly to the point. As soon as Silas Grimstone had told me his extraordinary story I realized that there would be some perfectly simple explanation. Phantoms do not walk in my book, neither do the dead return to plague the living. Therefore, I was looking for an elaborate masquerade. I wanted a man who knew the marshes; a stranger possibly, who had taken the trouble to map the secret paths; one who probably knew something about Grimstone's past and intended to frighten him by dressing up in the phosphorescent clothing we have already seen."
"But for what purpose?"
"We are coming to that, Parker. I first needed the method by which the phantom appeared and disappeared in such a startling manner; then a possible refuge in the marsh where he could hide and don his disguise; and finally, some corroboration from others that the apparition was not limited to Grimstone alone. I obtained all three in fairly short order."