A genuine, safe, pleasing paste for the
     teeth, prepared and sold only by the
     Auer Dental Company, New York.

Fleck’s eyes gleamed with satisfaction as he read this advertisement and caught the phrase “wonder-working.”  He felt sure now that he was on the right track.  He recalled that Jane Strong over the dictograph had heard old Hoff speak of something that he called the “wonder-worker.”  As soon as Carter returned with the other advertisements that had been appearing he felt positive that he would be able to unravel the cipher.  Two words he was sure of—­“passports” and “wonder-working.”  One footprint does not lead anywhere, but two do, and given three footprints, a pathway is indicated.

His telephone rang sharply.  He turned to answer it, suspecting it must be Carter with some message about the papers he had sent for.

“Hello,” he called.

“Hello,” came a faint voice, as if the speaker were using long distance, and had a bad connection, “is this Fleck?”

“Yes, Fleck,” he answered, “who is this?”

“Dean speaking,” came the voice faintly.

“Dean,” cried Fleck, excitedly, “yes, yes.  What is it, Dean?”

He had not expected to hear any results from the expedition that Dean and Jane Strong had undertaken until late in the afternoon after the Hoffs returned.  The fact that Dean was calling him up now would seem to indicate that something of importance had happened.

“I’m telephoning from a doctor’s house near Nyack,” said Dean.

“What’s that?  Speak louder.”

“I’m here in Doctor Spencer’s office near Nyack with a broken arm,” Dean continued.  “We’ve had an accident.  Somebody’s auto smashed into us, I guess.”

“Miss Strong?  Where is she?  Is she hurt?” asked the chief anxiously.

“I don’t know.  She has vanished.”

Jane Strong vanished!  The chief’s figure became suddenly tensed.  That it was more than a mere automobile accident he felt certain now.  Shadowing the Hoffs was an occupation that seemed unusually perilous.  There flashed into his mind the fate of K-19—­murdered almost at the Hoffs’ door.  And now two more of his operatives, one disabled and the other mysteriously missing.

“Quick,” he said over the ’phone.  “Tell me briefly just what happened.  Speak as loudly as you can.”

“We got half an hour behind at the West Point Ferry,” Dean’s voice went on, still weak and low as if he were speaking with difficulty.  “We had some trouble getting started on the trail again but finally succeeded.  We were dashing along about ten or twelve miles south of West Point when an automobile coming out of a cross road crashed right into us.  It must have knocked me unconscious.  I didn’t remember anything more till I found myself here.  I came to as the doctor was setting my arm.  I ’phoned as soon as they would let me.”

“Who brought you there?”