So he stood intently, motionlessly, listening, listening; but all was silent except for the monotonous dripping of water in one of the nooks of the court–yard, and the distant murmur of the river borne upon the breath of the night air. "Mayhap I was mistaken," muttered Schwartz Carl to himself.

But the next moment the silence was broken again by a faint, shrill whistle; what did it mean?

Back of the heavy oaken door of the tower was Schwartz Carl's cross–bow, the portable windlass with which the bowstring was drawn back, and a pouch of bolts. Schwartz Carl reached back into the darkness, fumbling in the gloom until his fingers met the weapon. Setting his foot in the iron stirrup at the end of the stock, he wound the stout bow–string into the notch of the trigger, and carefully fitted the heavy, murderous–looking bolt into the groove.

Minute after minute passed, and Schwartz Carl, holding his arbelast in his hand, stood silently waiting and watching in the sharp–cut, black shadow of the doorway, motionless as a stone statue. Minute after minute passed. Suddenly there was a movement in the shadow of the arch of the great gateway across the court–yard, and the next moment a leathern–clad figure crept noiselessly out upon the moonlit pavement, and stood there listening, his head bent to one side. Schwartz Carl knew very well that it was no one belonging to the castle, and, from the nature of his action, that he was upon no good errand.

He did not stop to challenge the suspicious stranger. The taking of another's life was thought too small a matter for much thought or care in those days. Schwartz Carl would have shot a man for a much smaller reason than the suspicious actions of this fellow. The leather–clad figure stood a fine target in the moonlight for a cross–bow bolt. Schwartz Carl slowly raised the weapon to his shoulder and took a long and steady aim. Just then the stranger put his fingers to his lips and gave a low, shrill whistle. It was the last whistle that he was to give upon this earth. There was a sharp, jarring twang of the bow–string, the hiss of the flying bolt, and the dull thud as it struck its mark. The man gave a shrill, quavering cry, and went staggering back, and then fell all of a heap against the wall behind him. As though in answer to the cry, half a dozen men rushed tumultuously out from the shadow of the gateway whence the stranger had just come, and then stood in the court–yard, looking uncertainly this way and that, not knowing from what quarter the stroke had come that had laid their comrade low.

But Schwartz Carl did not give them time to discover that; there was no chance to string his cumbersome weapon again; down he flung it upon the ground. "To arms!" he roared in a voice of thunder, and then clapped to the door of Melchior's tower and shot the great iron bolts with a clang and rattle.

The next instant the Trutz–Drachen men were thundering at the door, but Schwartz Carl was already far up the winding steps.

But now the others came pouring out from the gateway. "To the house," roared Baron Henry.

Then suddenly a clashing, clanging uproar crashed out upon the night. Dong! Dong! It was the great alarm bell from Melchior's tower—Schwartz Carl was at his post.

Little Baron Otto lay sleeping upon the great rough bed in his room, dreaming of the White Cross on the hill and of brother John. By and by he heard the convent bell ringing, and knew that there must be visitors at the gate, for loud voices sounded through his dream. Presently he knew that he was coming awake, but though the sunny monastery garden grew dimmer and dimmer to his sleeping sight, the clanging of the bell and the sound of shouts grew louder and louder. Then he opened his eyes. Flaming red lights from torches, carried hither and thither by people in the court–yard outside, flashed and ran along the wall of his room. Hoarse shouts and cries filled the air, and suddenly the shrill, piercing shriek of a woman rang from wall to wall; and through the noises the great bell from far above upon Melchior's tower clashed and clanged its harsh, resonant alarm.

Otto sprang from his bed and looked out of the window and down upon the court–yard below. "Dear God! what dreadful thing hath happened?" he cried and clasped his hands together.

A cloud of smoke was pouring out from the windows of the building across the court–yard, whence a dull ruddy glow flashed and flickered. Strange men were running here and there with flaming torches, and the now continuous shrieking of women pierced the air.

Just beneath the window lay the figure of a man half naked and face downward upon the stones. Then suddenly Otto cried out in fear and horror, for, as he looked with dazed and bewildered eyes down into the lurid court–yard beneath, a savage man, in a shining breast–plate and steel cap, came dragging the dark, silent figure of a woman across the stones; but whether she was dead or in a swoon, Otto could not tell.

And every moment the pulsing of that dull red glare from the windows of the building across the court–yard shone more brightly, and the glare from other flaming buildings, which Otto could not see from his window, turned the black, starry night into a lurid day.

Just then the door of the room was burst open, and in rushed poor old Ursela, crazy with her terror. She flung herself down upon the floor and caught Otto around the knees. "Save me!" she cried, "save me!" as though the poor, pale child could be of any help to her at such a time. In the passageway without shone the light of torches, and the sound of loud footsteps came nearer and nearer.

And still through all the din sounded continually the clash and clang and clamor of the great alarm bell.

The red light flashed into the room, and in the doorway stood a tall, thin figure clad from head to foot in glittering chain armor.