house was always open to him. While he had not ignored the invitations,
he had never responded in person. He began to experience twinges of
remorse: Medcroft was such a good fellow!

The Londoner did not respond to the innocuous query. He merely stared
in a preoccupied, determined manner at the succeeding _étages_ as they
slipped downward. At the fourth floor they disembarked, and Brock led
the way to his rooms, overlooking the inner court. Once inside, with the
door closed, he turned upon the Englishman.

"Now, what's up, Rox? Are you in trouble?" he demanded.

"Are we quite alone?" Medcroft glanced significantly at the transom and
the half-closed bathroom door. With a laugh, Brock led him into the
bathroom and out, and then closed the transom.

"You're darned mysterious," he said, pointing to a chair near the
window. Medcroft drew another close up and seated himself.

"Brock," he said, lowering his voice and leaning forward impressively,
"I want you to go to Vienna in my place." Brock stared hard. "You are a
godsend, old man. You're just in time to do me the greatest of favours.
It's utterly impossible for me to go to Vienna as I had planned, and yet
it is equally unwise for me to give up the project. You see, I've just
got to be in London and Vienna at the same time."

"It will require something more than a stretch of the imagination to do
that, old man. But I'm game, and my plans are such that they can be
changed readily to oblige a friend. I shan't mind the trip in the least
and I'll be only too happy to help you out! 'Gad, I thought by your