There was no mistaking--this was the voice of his "friend and
well-wisher" over the telephone.

The other said something in German in a hoarse whisper. Having studied
that language in college, Aubrey caught only two words--Thur and
Schlussel, which he knew meant door and key.

"Very well," said the first voice. "That will be all right, but we
must act to-night. The damned thing must be finished to-morrow. Your
idiotic stupidity--"

Again followed some gargling in German, in a rapid undertone too fluent
for Aubrey's grasp. The latch of the alley gate clicked once more, and
his hand was on his revolver; but in a moment the two had passed on
down the alley.

The young advertising agent stood against the fence in silent horror,
his heart bumping heavily. His hands were clammy, his feet seemed to
have grown larger and taken root. What damnable complot was this? A
sultry wave of anger passed over him. This bland, slick, talkative
bookseller, was he arranging some blackmailing scheme to kidnap the
girl and wring blood-money out of her father? And in league with
Germans, too, the scoundrel! What an asinine thing for old Chapman to
send an unprotected girl over here into the wilds of Brooklyn . . . and
in the meantime, what was he to do? Patrol the back yard all night?
No, the friend and well-wisher had said "We must find some other way."
Besides, Aubrey remembered something having been said about the old
terrier sleeping in the kitchen. He felt sure Bock would not let any
German in at night without raising the roof. Probably the best way
would be to watch the front of the shop. In miserable perplexity he
waited several minutes until the two Germans would be well out of
earshot. Then he unbolted the gate and stole up the alley on tiptoe,
in the opposite direction. It led into Wordsworth Avenue just behind
Weintraub's drug store, over the rear of which hung the great girders
and trestles of the "L" station, a kind of Swiss chalet straddling the
street on stilts. He thought it prudent to make a detour, so he turned
east on Wordsworth Avenue until he reached Whittier Street, then
sauntered easily down Whittier for a block, spying sharply for
evidences of pursuit. Brooklyn was putting out its lights for the
night, and all was quiet. He turned into Hazlitt Street and so back
onto Gissing, noticing now that the Haunted Bookshop lights were off.
It was nearly eleven o'clock: the last audience was filing out of th