“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.