"One thing," Garth asked. "How did you have the nerve to drive your limousine to the place last night?"
"I didn't," Black answered. "I picked it up in Third Avenue."
He did not speak again, and Garth no longer urged him. He walked straight for the block in which he had been at his folly last night. But he did not pause there. He continued across Lexington Avenue and made confidently for the deserted, dust-filled house which just now had mocked the police. Garth, amazed, followed him to the basement door.
Black took a key from his pocket, and with the ease of long habit inserted it through the obscurity in the lock. The door opened and Garth walked into the blackness with a quickening suspense. His apprehension was for Nora rather than himself. What had happened to her when she had stepped into the dusty hall? Her only chance was that he would not be caught in this somber pit as she had probably been. He put his hand on his revolver.
"Go first," he whispered.
The darkness was so complete that Garth had to keep his fingers on the other's arm to avoid stumbling against the walls. Yet his guide went with a quick assurance to the rear door which he opened with another key. They stepped beneath a rough shelter of corrugated iron such as is hastily thrown up for the protection in summer of washboards, or, in winter, for the storing of wood. Black proceeded beneath this shelter along the fence to the corner. Garth noticed a large accumulation of rubbish in the yard, souvenirs, doubtless, of indolent and utilitarian neighbors.
Black stooped. Evidently he had given a signal which Garth had not seen or heard, for straightway he arose and leant against the fence, waiting.
"What now?" Garth asked.
Black raised his finger to his lips.
Garth looked down at a rustling among the rubbish. A thin piece of flagging had opened at his feet as if hinged like a trap-door, leaving visible the top of a flight of rough wooden steps.