For a moment, grim-lipped, Locke stood there at the door. He had accomplished exactly the opposite to what he had intended—the old man, the money, were both in infinitely greater peril now than under almost any other circumstances of which he could conceive. He did not blame himself—the vagaries, the impulses, the irrational promptings of an insane mind were beyond his control or guidance. It was the last thing he had expected the old maniac to do. But it was done now; it was too late to consider that phase of it. There was work for his own brain to do—he hoped more logically.

He turned sharply now, and began to make his way as best he could in the darkness toward the window at the end of that aisle of tanks outside of which he knew the masked man had stood. He dared not show any light here, though by so doing he would have been able to move more swiftly. The man who had been at the window was almost certainly gone now—to watch for the old maniac's appearance outside the house. And Mr. Marlin would assuredly, and as quickly as he could, scurry outside to hide his money away again. And even if the man in the mask had had no previous knowledge of the old madman's strange nightly movements, which would be a very unsafe assumption on which to depend, he would have heard enough at the window, if not to know, then, at least, to expect that the old maniac's one thought now would be to secrete his money, and that the hiding place, this time-lock that God had made, as the old man had called it, was somewhere outside the house. But the watcher's new lurking place might still embrace a view of the window, and if he, Locke, climbed out with the light behind him—

He was at the window now. He smiled grimly. He was pitted against no fool—but then he never had been fool enough himself ever to place Captain Francis Newcombe in that category! The man in the mask had left no tell-tale evidence of his presence behind him. The shade was drawn down; the window closed.

Locke lifted the shade now, raised the window quietly, and stood for an instant listening, staring out. He could see little or nothing, other than the swaying branches of trees against the sky line; and there was no sound save the sweep of the wind which was still blowing half a gale. And now he swung himself over the window sill, dropped the few feet to the ground—and crouched against the wall, listening, staring again into the blackness.

Nothing! The moon, burrowing deeper under the clouds, made it even blacker than it had been a moment ago. He straightened up and began to run toward the front of the house. It was perhaps a case of blindman's-buff, but there was not an instant to lose, and, deprived of any aid from the sense of either sight or hearing, he was left with only one thing to do. From the living room window a little while ago, he had seen Mr. Marlin coming toward the house from across the lawn, after having presumably just unearthed his money from its hiding place; the chances were that it was by the same route the old maniac would return now.

Locke ran on, stumbling, half groping his way through what seemed a veritable maze of out-buildings here at the rear of the house. The minutes seemed to be flying—wasted. The old maniac, if he had left the house the moment he had run from the aquarium, must by now have had a good three minutes' start; and if the man in the mask had at once picked up the trail, then—

No; he was not too late! He had reached the front corner of the house now, and across the lawn, where in the open space it was a little lighter, something, a blacker thing than the darkness, moving swiftly, caught his eye. It was the figure of a man running toward the trees in the direction of the path that led to the shore, and from which old Mr. Marlin had emerged earlier in the evening. And now the figure was gone—lost in the trees.

But he, Locke, too, was running now, sprinting for all he knew across the lawn. It was perhaps sixty yards. There was no time to use caution and circuit warily around the edge of the woods. He might be seen—but he had to take that chance. He would not be heard—the soft grass and the whine of the wind guaranteed him against that. It was a little better than an even break. The figure he had seen was not, he was sure, that of the old maniac. The long, flapping dressing gown would, even in a shadowy way, have been distinguishable. If he were right, then, in his supposition, the figure he had seen was the man in the mask, and old Mr. Marlin was already in there on the path leading through the woods to the shore. A cry, sudden, like a scream that was strangled, came with the gusting wind. It came again. From the edge of the lawn now, Locke leaped forward along the path. Black, twisting shapes loomed up just ahead of him. He flung himself upon them.

A low, startled, vicious snarl answered his attack. After that there was no sound while perhaps a minute passed, save the rustle of leaves and foliage, the snip of broken twigs under swiftly moving, straining feet. Locke was fighting now with merciless, exultant ferocity. It was the man in the mask he was at grips with—it was not the dressing gown alone, the feel of it, that distinguished one from the other; he had even in that first plunging rush in the darkness felt his hand brush against the mask on the man's cheek.

It was all shadow, all blackness. To this side and that, close locked together, he and his antagonist now swayed madly. The man's one evident desire was to break away from his, Locke's, encircling arms; his, Locke's, purpose not only to prevent escape, but to unmask the other—the moon might come out again at any instant—filter through the branches—just enough light to see the other's face if the mask were off.