There had reached his ear a sound, though a bit muffled, which he instantly recognized—the sharp, spiteful crack of a revolver.

“Come on, Doyle,” he snapped quickly. “That smacks of big game, all right. I reckon we’re in the nick of time.”

Nick was running at top speed through the alley while speaking, with the burly policeman close on his heels.

Ten seconds brought them to the back door of the building—which Patsy Garvan had left unlocked.

Nick then heard the shouts of men within, and the furious voice of Gaston Goulard.

“We’ve got them, Doyle,” he said quietly, pausing for an instant. “Are you ready?”

“I’ll go ahead, if you say the word.”

“Not much!”

Nick turned the knob and threw open the door, shedding the bright daylight into the dim hall in which Goulard, Bart Bailey, Nolan, and Bolton were attempting with fierce threats to subdue Chick and Patsy, who had smashed the lamps in the subterranean chamber only a moment before.

Nick broke in upon them with his revolver ready, shouting sternly: