t a queer chap! If it weren't that he touched me as he passed,
and I felt that he was flesh and blood, I should be inclined to
think he was a ghost. I wonder what he is up to?"

"Examine the paper. Doubtless that will enlighten us," said the
practical Osterberg. "If I'm not mistaken, this is some game, in
which we are wanted to participate."

George examined the paper, turning it over and over wonderingly. It
was a dirty envelope, of the cheaper kind, sealed down and addressed
to him.

"The mystery deepens. It's from some one who knows me, evidently.
The writing seems familiar, too. I wonder----"

"Confound it, man, open it!" broke in his impatient companion. "You
are right about the handwriting. It _is_ familiar."

Helmar tore the envelope open, and examined the contents. It was a
brief note, signed by Mark Arden.

The two read the contents eagerly.

"Dear George,

"I have just found out you are in the town. For certain reasons, I
cannot meet you in public; but, if you will meet me at the last
Mosque outside the town, on the lake's edge (any one can direct
you), in half-an-hour, I shall be glad to return you the money I
borrowed at Varna.

"Yours ever,

"Mark."

As they finished reading this extraordinary epistle, the two young
men silently looked at one another. Osterberg was the first to break
the silence.

"Well, of all the unadulterated cheek I ever heard of, this beats
everything! I suppose he's going to pay you out of what he stole
from the barracks. What are you going to do about it?"

Helmar looked long at the paper before replying. He was trying to
find out what lay hidden under these lines. Somehow, he could not
bring himself to believe in their genuineness. There was a deeply
suspicious air about the whole thing, not the least being the
delivery of the note. At last he appeared to make up his mind.

"We'll see it through. If there is any trickery, I dare say we can
hold our own. Will you come?"

"Rather!" cried his friend. "But have we time?"

Helmar looked at his watch. It still wanted two hours to the time he
must be aboard the transport, and he had no doubt the quay could be
reached in time.

"Oh, yes, heaps of time! We'd better find out where this particular
Mosque is. We'll ask the first person we meet."

At this moment an elderly Arab came along from behind, as if in
answer to his expressed intention, and Helmar stopped him, and
inquired the way