The woman sank into a chair.

“You can’t be from the home office,” she muttered, staring hard at the girl.  “They wouldn’t dare interfere with my work here.”

“No; I’m not from the home office.”

“I knew,” said Susan, “as soon as I heard the story of your coming, that it was faked.  I’d gamble that you never saw Mrs. Morrison in your life.”

“You’d win,” said Sarah, also taking a chair.

“Then who could have sent you here?”

“Figure it out yourself,” suggested Sarah.

“I’m trying to.  Do you know what we’re after?”

“A clew to Hathaway.  Incidentally, any other information concerning him that comes your way.  That includes the letter.”

“Oh.  So you know about the letter, do you?” asked Susan.

“To be sure.  And I know that’s what you’re here for now.  Don’t let me interrupt you.  It’s a mighty hard job, finding that letter, and the folks’ll be back by and by.”

“You’re right,” exclaimed the woman, rising abruptly.  “Go back to your work in the kitchen.”

“This is my occupation, just now,” retorted Sarah, lolling in her chair.  “Go ahead with your search, Nan, and I’ll tell you when you are ‘hot’ or ‘cold.’”

“You’re an impudent little chit,” said Nan tartly.  “See here,” with a sudden change of voice, “let’s pool issues.  If we can discover anything important in this place, there’s reward enough for us all.”

“I am not opposing you,” protested Sarah Judd, “I’m not a particle interested in whether you trace Hathaway or not.  I don’t believe you can do it, though, and that letter you’re so eager for won’t help you a bit.  It was written ten years ago.”

“That makes it more important,” declared the other, “We’ve two things to accomplish; one is to locate Hathaway, and the other to secure absolute proof of his guilt.”

“I thought he was caught doing the job.”

“So he was, in a way.  But the Department needs more proof.”

Sarah Judd smiled unbelievingly.  Then she chuckled.  Presently she laughed outright, in genuine merriment, as the thought that amused her grew and expanded.

“What fools—­” she said, “what perfect fools—­we mortals be!”

All this annoyed Nan Shelley exceedingly.  The successful woman detective did not relish being jeered at by a mere girl.

“You’ve read the letter, I suppose, and are now making fun of me for trying to get it?  Perhaps you’ve hidden it yourself—­although that isn’t likely.  Why can’t you give me an honest tip?  We’re both in the same line, it seems, and both trying to earn an honest living.  How about that letter?  Is it necessary for me to find it?”

“I’ve read it,” admitted Sarah, “and I know where it is.  You might perhaps find it, if you hunted long enough, but it isn’t worth your while.  It wouldn’t help in the least to convict Hathaway and of course it couldn’t tell you where he is now hiding.”