Then Marco recognized that a curious thing happened.  The Lovely Person saw the movement and the gray moustache, and that instant her smile died away and she turned quite white—­so white, that under the brilliant electric light she was almost green and scarcely looked lovely at all.  She made a sign to the man on the staircase and slipped through the crowd like an eel.  She was a slim flexible creature and never was a disappearance more wonderful in its rapidity.  Between stout matrons and their thin or stout escorts and families she made her way and lost herself—­but always making toward the exit.  In two minutes there was no sight of her violet draperies to be seen.  She was gone and so, evidently, was her male companion.

It was plain to Marco that to follow the profession of a spy was not by any means a safe thing.  The Chancellor had recognized her—­she had recognized the Chancellor who turned looking ferociously angry and spoke to one of the young officers.

“She and the man with her are two of the most dangerous spies in Europe, She is a Rumanian and he is a Russian.  What they wanted of this innocent lad I don’t pretend to know.  What did she threaten?” to Marco.

Marco was feeling rather cold and sick and had lost his healthy color for the moment.

“She said she meant to take me home with her and would pretend I was her son who had come here without permission,” he answered.  “She believes I know something I do not.”  He made a hesitating but grateful bow.  “The third act, sir—­I must not keep you.  Thank you!  Thank you!”

The Chancellor moved toward the entrance door of the balcony seats, but he did it with his hand on Marco’s shoulder.

“See that he gets home safely,” he said to the younger of the two officers.  “Send a messenger with him.  He’s young to be attacked by creatures of that kind.”

Polite young officers naturally obey the commands of Chancellors and such dignitaries.  This one found without trouble a young private who marched with Marco through the deserted streets to his lodgings.  He was a stolid young Bavarian peasant and seemed to have no curiosity or even any interest in the reason for the command given him.  He was in fact thinking of his sweetheart who lived near Konigsee and who had skated with him on the frozen lake last winter.  He scarcely gave a glance to the schoolboy he was to escort, he neither knew nor wondered why.

The Rat had fallen asleep over his papers and lay with his head on his folded arms on the table.  But he was awakened by Marco’s coming into the room and sat up blinking his eyes in the effort to get them open.

“Did you see him?  Did you get near enough?” he drowsed.

“Yes,” Marco answered.  “I got near enough.”

The Rat sat upright suddenly.

“It’s not been easy,” he exclaimed.  “I’m sure something happened—­something went wrong.”

“Something nearly went wrong—­very nearly,” answered Marco.  But as he spoke he took the sketch of the Chancellor out of the slit in his sleeve and tore it and burned it with a match.  “But I did get near enough.  And that’s two.”