“It is impossible to say at this stage of the proceedings.  All we can tell is that there is some plot going on.  You refused, of course, to allow Mitchell to come back to the house?”

“Yes.  You think that was wise?”

“Undoubtedly.  If his absence did not handicap them, they would not be so anxious to have him on the spot.”

“What shall we do?”

“You wish me to undertake the case?”

“Of course.”

Mr. Sturgis frowned thoughtfully.

“It would be useless for me to come here myself.  By bad luck the man who pretends to be your nephew has seen me.  If I were to come to stay here, he would suspect something.  He would be on his guard.”  He pondered with closed eyes.  “Miss Trimble,” he exclaimed.

“I beg your pardon.”

“You want Miss Trimble.  She is the smartest worker in my office.  This is precisely the type of case she could handle to perfection.”

“A woman?” said Mrs. Pett doubtfully.

“A woman in a thousand,” said Mr. Sturgis.  “A woman in a million.”

“But physically would a woman be—?”

“Miss Trimble knows more about jiu-jitsu than the Japanese professor who taught her.  At one time she was a Strong Woman in small-time vaudeville.  She is an expert revolver-shot.  I am not worrying about Miss Trimble’s capacity to do the work.  I am only wondering in what capacity it would be best for her to enter the house.  Have you a vacancy for a parlour-maid?”

“I could make one.”

“Do so at once.  Miss Trimble is at her best as a parlour-maid.  She handled the Marling divorce case in that capacity.  Have you a telephone in the room?”

Mrs. Pett opened the stuffed owl.  The detective got in touch with his office.

“Mr. Sturgis speaking.  Tell Miss Trimble to come to the phone. . . .  Miss Trimble?  I am speaking from Mrs. Pett’s on Riverside Drive.  You know the house?  I want you to come up at once.  Take a taxi.  Go to the back-door and ask to see Mrs. Pett.  Say you have come about getting a place here as a maid.  Understand?  Right.  Say, listen, Miss Trimble.  Hello?  Yes, don’t hang up for a moment.  Do you remember those photographs I showed you yesterday?  Yes, the photographs from Anderson’s.  I’ve found the man.  He’s the butler here.  Take a look at him when you get to the house.  Now go and get a taxi.  Mrs. Pett will explain everything when you arrive.”  He hung up the receiver.  “I think I had better go now, Mrs. Pett.  It would not do for me to be here while these fellows are on their guard.  I can safely leave the matter to Miss Trimble.  I wish you good afternoon.”

After he had gone, Mrs. Pett vainly endeavoured to interest herself again in her book, but in competition with the sensations of life, fiction, even though she had written it herself, had lost its power and grip.  It seemed to her that Miss Trimble must be walking to the house instead of journeying thither in a taxi-cab.  But a glance at the clock assured her that only five minutes had elapsed since the detective’s departure.  She went to the window and looked out.  She was hopelessly restless.