"Correct. Now pick out a German and trail him."

"Yes sir. And you—?"

"I'll do the same—as well as every other member of the Criminology Club. I want to know every move they are making."

Turner moved away. Harrison Grant stepped forward, chatted a moment with a young woman of his acquaintance—then stared.

Before him, coming toward the young woman at his elbow, was quite the prettiest girl—to Harrison Grant's eyes—that he had ever seen. Vivacious, beautifully dressed, full of the dash and verve that Harrison Grant so admired, quick, decisive in her movements, yet thoroughly girlish, there was an element about her that Harrison Grant had never before noticed in another woman. Something within him seemed to leap, hesitate, then begin to thump with the quickness and persistence of a triphammer. Vaguely Grant knew that it was his heart. And just as vaguely, he knew that he was being introduced to this brown-eyed, smiling little being, whose hand was so small that it seemed almost cruelty to press it—yet with a grasp so firm and steady that it carried with it the sensing touch of a true, strong companion—whose hair was black and yet brown, whose smile was frank and yet elusive, whose whole being was of the sort to enthrall Harrison Grant and to hold him prisoner.

Then a sudden change. The beating of his heart slowed. The sparkle of his eyes dulled. The smile faded from his lips—for just behind the girl whose name he had vaguely heard to be Miss Dixie Mason, had shown the figure of her escort, a man whom Grant had come to hate, a man he knew to be responsible for the working out of the plot against the Ansonia Hotel that night, Heinric von Lertz, unofficial agent for Imperial Germany's murderers.

As for Von Lertz, he turned somewhat quizzically toward the policeman at the door of the ballroom, looked at him in a sneering fashion, then with a short nod in acknowledgment of the introduction to Grant, he asked:

"Police? Is it the usual thing in America for them to attend social functions?"

"Not unless they're invited—or needed," answered Harrison Grant caustically.

A quick glance shot between the two men. A moment more and Von Lertz had turned to the ballroom, taking Dixie Mason with him, while Harrison Grant watched after her, wondering what such a pretty, wholesome appearing girl could be doing in the company of a man whose business was the representation of murderers. That she carried a Secret Service commission, Grant did not know. The instructions of Chief Flynn, ordering her to work into the confidence of the Germans without letting even the fellow members of the Secret Service know her true purpose, had attended to that. And Grant saw in her only a girl who had chosen as a companion a man who was at that moment plotting the very downfall of America!