The course led upward; for the man ahead was mounting to the fourth floor. He reached his destination and paused. He stood beside a little window that opened into a high-walled courtyard. He remained there, peering out into the dim, vague light that gave but slight visibility to the narrow area.
While he was standing there, a mass of blackness grew behind him; then became as motionless as a statue. The man at the window turned. He stared almost directly at the peculiar form close beside him, but his eyes saw nothing.
Then the sharp-faced man walked to the nearest door, a few paces down the corridor, and tapped softly. The door clicked; stealthily it pushed open an inch — then two. The man brushed inside. The door closed silently.
Even as the trailed one stepped into the apartment, the black form in the hallway swept toward the window. The sash glided upward. Then the figure of a man projected itself outward. The window moved softly down.
The dim glow of the courtyard revealed a shadowy mass, poised upon the courtyard wall. A long arm crept sidewise like a living creature. It found an ornamental shaft of brick. The entire form followed the arm.
Foot by foot, the black shape pursued a lizardlike course along the perpendicular side of the wall!
The man with the wolfish face was not present to view this miraculous occurrence. He was safely in the apartment.
While events were taking place upon the wall of the courtyard, he was hanging his hat and coat on a hook at the end of a small entryway.
That accomplished, he stepped into a dimly lighted room. It had two windows, side by side, opening on the courtyard. Shades were drawn over the windows.
THE room already had one occupant. A man was sitting in the corner beside a table. The table bore a telephone. The man was directly beneath the light of the shaded lamp which illuminated the room.