Mr. Mountain went into the lobby, and Chick asked an attendant if there was a way out of the room except through the lobby. An unknown way was pointed out, and through it Chick and Patsy went out to Broadway. Here Chick said: “Now, Patsy, go into the theatre and keep up the watch. I think Mountain will be shadowed home; follow if he is. I shall hunt up the chief.” Patsy obeyed, and went into the theatre, paying his admission, to see the man he had followed earlier in the day, in the same disguise in which he had come from the Seventeenth Street house; that is to say, the Brown Robin, standing just within the audience hall. He took up a standing position near her. Chick hurried across town to Nick’s apartments and arrived a few minutes after Nick had returned from his walk with Edith. The famous detective listened intently to what Chick had to tell. “This is great work of yours, Chick,” he said. “You have proved satisfactorily what I have suspected ever since I was at the Brown Robin’s house as Mr. Cary. “The suspicion that the man that followed me this morning and was followed by Patsy afterward was a woman came to me when he took me to the Lexington house.” “I was looking for the knock-kneed gait that the keen-witted Patsy spoke of, and then it struck me it was a woman, well padded and made up.” “But, chief, you saw the man go out of the Lexington Avenue house just as the Brown Robin came to you.” “No, I didn’t, Chick,” replied Nick, with a smile. “I heard it. But I dropped then, or thought I did, that the two voices were from the same person—a little play played for my benefit. “She is a great actress, Chick, and a thundering smart woman. She has the energy of the devil. When she left me, as Mr. Cary, in Twenty-third Street, she must have come straight over here. Leaving here, she made for the Seventeenth Street house, to make her change for the night’s work. “That was a great piece of work of yours to go into that house. It proved the fact, and shows up her game. “I can see now how she baffled all the others. She has three houses to work in, and in the Lexington Avenue house she is seen only as a woman, except as she ordered it to-day. “She is great on makeup, and she plays the game herself. Well, she makes the big strike to-morrow, and we’ll have her. “We’ll meet her with her own cunning. “But come, we’ll go to Mr. Mountain’s house, to be there before he gets back from the theatre. “Take my word for it, Chick, the Thirtieth Street house is to be the scene of the big strike.” With this, the two detectives set out for Mr. Mountain’s residence. CHAPTER IX. THE TRAP. Patsy arrived early the next morning to report to Nick that on the night previous the Brown Robin, still in male attire, had followed Mr. Mountain to his home, after that gentleman had left the theatre with his family.