“609 is moving out tonight. Would that be time enough—or do you want it now?”

“No, that’s plenty of time. And another thing, can you tell me where Mrs. Weinberger’s room is? I met her at Stoddard House, and she would be a sort of chaperon for me.”

“Her room is on the tenth floor,” was the reply: “1026.”

“Thanks. Then put me down for 609, and I’ll phone Mrs. Weinberger this afternoon. I’ll come back early this evening, and I’ll ask Mrs. Weinberger to meet me in one of the reception rooms. Then, could you come there too, Mr. Hayden?”

The man nodded, smiling. How correct this girl was about everything!

“Then I believe it’s all arranged,” said Mary Louise, rising. “I’ll go back to Stoddard House. And if you have a chance, Mr. Hayden, will you keep your eye on these girls we’re suspecting?”

“But I don’t know them,” he reminded her.

“I’d forgotten that! Well, let me describe them. Maybe if you visit the sixth floor, you will see them go in and out.”

She went on to tell him that Pauline Brooks—or Catherine Smith, as she called herself here—was a striking brunette, and that her companion, Mary Green—or Mary Jackson—was noticeably blond; that both girls were short and slender and wore fur coats and expensive jewelry; that both were as little like the typical sneak thieves as could possibly be imagined.

As Mary Louise walked along the street she decided not to tell Mrs. Hilliard any of the details of her plans or who the girls were that she was watching. If nothing came of her theory, she would feel foolish at having failed the third time. Besides, it wasn’t fair to the girls to spread suspicion about them until she had proved them guilty.