need me any longer."

"What is the building at Columbus Avenue and 96th Street?" Duvall asked,
as the man, pulling on the coat his wife handed him, strode down the
hall.

"An apartment building, sir."

"And why did Mrs. Duvall go there?"

"Well, sir, we was following a woman, sir. She went to a hotel on
Seventy-second Street, and Mrs. Duvall told me to watch for her. I did,
and tracked her to the place at 96th Street. Then I telephoned to Mrs.
Duvall to come, and she did."

"What time was that?"

"About half-past nine, sir."

"All right. Go on."

"Mrs. Duvall came, sir, in another taxi. I pointed out the place where
the woman went in, and Mrs. Duvall went in after her. She didn't say I
was to wait, but I guess she expected me to, because she had sent the
other cab away. I waited over two hours, and then, when she didn't come
out, I supposed she had returned to her hotel, so I came back, too. She
wasn't there, though. That's why I left the note."

"How did you think Mrs. Duvall could have gotten back to her hotel, if
you were watching the door of the apartment house all the time?"

"I wasn't watching it all the time, sir. I went into the drug store
once, sir, and got a cigar. And then, later on, I went to a saloon a
piece down the Avenue and got a glass of beer. Mrs. Duvall didn't say I
was to watch the place, sir. I thought when she got through what she had
to do, she would come back to the cab. But she didn't. Do you think I
ought to have waited, sir?" The man seemed greatly distressed.

"No use talking about that now," Duvall remarked, shortly. "I want to
drive there at once. Get on the box, with the chauffeur, and point out
the place to him."

"Yes, sir." A moment later they had started on their way uptown.

Knowing as he did Grace's impetuous nature, Duvall could only conclude
that her pursuit of the woman had led her into some trap. What danger
she might at this moment be facing, he could only surmise. The apartment
building, when they finally reached it, presented a grim and forbidding
appearance. Not a light broke the darkness of any of its windows. The
drug store on the opposite corner, too, was closed for the night. The
whole locality was dark and silent.

"There's the place, sir," Leary exclaimed, as they drew up to the
corner.

"Tell the driver to stop a few doors up the block--not right in front of
the building."

Leary nodded. Presently the cab stopped, and he and Duvall got out.

Th