"Well then, I will," he muttered, gritting his teeth. Johnny was a
trifle out of sorts to-night. The chase annoyed him.

He dodged down the alley, then up a narrow court. Prying open the window
of an empty building, he crept in and silently slid the sash back in its
place. Tiptoeing across the hall with the lightness of a cat, he crept
up the dusty stairs. One, two, three flights he ascended, then feeling
for the rounds of a short ladder, he climbed still higher, to lift a
trapdoor at last and creep out upon the roof.

Once there he skulked from chimney to chimney until he had crossed the
flat roofs of three buildings. The third had a trapdoor close to a
chimney. This he lifted, then dropped behind him. He was now in his own
building. Panting a little from the exertion, he tiptoed down the hall,
turned the key and entered his room.

Having made sure that the iron blinds were closed, he snapped on a
light. His eyes, roving around the room, fell presently upon something
white on the floor. Johnny could see his own name scrawled upon it.
There were but a few people in all the world who knew that Johnny
Thompson had ever lived here. Probably all of those who did know thought
him dead and buried in Russia. Who had written this note? Friend or foe?

He tore open the envelope and glanced at the note. It came to the point
with brutal frankness.

"Johnny Thompson: You are known to have in your possession rare gems
which do not belong to you. You will please leave them on the doorstep
of 316 North Bird place, and rap three times before you leave.