“Now,” said the Tracer of Lost Persons in a low voice to Captain Harren, “I am going to ask you to sit here for a few minutes while I interview the assistant curator.  You don’t mind, do you?”

“No, I don’t mind,” said Harren wearily, “only, when are we going to begin to search for—­her?”

“Very soon—­I may say extremely soon,” said Mr. Keen gravely.  “By the way, I think I’ll take that sheet of paper on which I copied the cipher.  Thank you.  I won’t be long.”

The attendant had vanished.  Captain Harren sat down by a window and gazed out into the late afternoon sunshine.  The Tracer of Lost Persons, treading softly across the carpeted floor, approached the sanctuary, turned the handle, and walked in, carefully closing the door behind him.

There was a young girl seated at a desk by an open window; she looked up quietly as he entered, then rose leisurely.

“Miss Inwood?”

“Yes.”

She was slender, dark-eyed, dark-haired—­a lovely, wholesome young creature; gracious and graceful.  And that was all—­for the Tracer of Lost Persons could not see through the eyes of Captain Harren, and perhaps that is why he was not able to discern a miracle of beauty in the pretty girl who confronted him—­no magic and matchless marvel of transcendent loveliness—­only a quiet, sweet-faced, dark-eyed young girl whose features and figure were attractive in the manner that youth is always attractive.  But then it is a gift of the gods to see through eyes anointed by the gods.

The Tracer touched his gray mustache and bowed; the girl bowed very sweetly.

“You are Mr. Keen,” she said; “you have an inscription for me to translate.”

“A mystery for young eyes to interpret,” he said, smiling.  “May I sit here—­and tell my story before I show you my inscription?”

“Please do,” she said, seating herself at her desk and facing him, one slender white hand supporting the oval of her face.

The Tracer drew his chair a little forward.  “It is a curious matter,” he said.  “May I give you a brief outline of the details?”

“By all means, Mr. Keen.”

“Then let me begin by saying that the inscription of which I have a copy was probably scratched upon a window pane by means of a diamond.”

“Oh!  Then—­then it is not an ancient inscription, Mr. Keen.”

“The theme is ancient—­the oldest theme in the world—­love!  The cipher is old—­as old as King Solomon.”  She looked up quickly.  The Tracer, apparently engrossed in his own story, went on with it.  “Three years ago the young girl who wrote this inscription upon the window pane of her—­her bedroom, I think it was—­fell in love.  Do you follow me, Miss Inwood?”

Miss Inwood sat very still—­wide, dark eyes fixed on him.

“Fell in love,” repeated the Tracer musingly, “not in the ordinary way.  That is the point, you see.  No, she fell in love at first sight; fell in love with a young man whom she never before had seen, never again beheld—­and never forgot.  Do you still follow me, Miss Inwood?”