It was well, perhaps, that he did so, for just then a man in a domino like his own accosted the girl. Roly saw his guide shrink away, saw her turn and signal him with a swift, imperious gesture of warning. Instead of heeding it, he moved forward in time to intercept the stranger. The fellow was laughing loudly; he assumed a tipsy air and lurched against the girl; then, with a quickness that belied his pose, he snatched at her mask and bared her features. She cried out in terror, and with the sound of her voice Mr. Van Dam flew to action. He knew that until six o'clock disguises were inviolate, and that it was against the strictest of police regulations to unmask a reveler; therefore he yielded to a righteous impulse and struck the man in the domino squarely upon the jaw. Beneath Roly's rounded proportions was a deceptive machinery of bone and muscle that had been schooled by the most expensive instructors of boxing. He had known how to hit cleanly since he was twelve years old, and although he had never struck a man in anger until this moment, his fist went true. The fellow rocked stiffly back upon his heels and fell like a wooden figure, his head thumping dully on the pavement, and Roly gave vent to a most ungentlemanly snort of surprise and satisfaction. It had been much easier than he had expected, and feeling that the man should have every opportunity for fair play Roly began promptly to count, "One, two, three—" Then he felt the girl's hand upon his arm, and turned in time to catch a fleeting glimpse of a dimpled chin as she drew her mask down. "Rotten trick, that!"
"Heaven above!" she gasped. "You must flee—quickly!"
People were crossing the street toward them, drawn by the sight of the fallen man.
"Run away and leave you?" queried Roly. "Hardly!"
"Then"—the breath caught in the girl's throat—"come!"
She clutched his hand and they fled, side by side, pursued by half a score of shouting merrymakers. Around the first corner they scurried, into a crowd, then out of it and into the next thoroughfare, doubling and turning until the girl's breath was gone.
"Why—did—you do—it? Ah!—why?" she gasped, still hurrying him along.
"Drunken loafer!" Van Dam said, vindictively.
"He was not drunk! Don't you understand? Didn't you guess? It was the Black Wolf!"
Roly did not understand, and he had no opportunity to guess who or what the Black Wolf might be, for his companion paused, crying: