[Transcriber's note: Extensive research found no evidence that the U.S. copyright on this publication was renewed.] I. THE BLACK IMP II. A MYSTERIOUS PACKAGE III. THE THREAT IV. FOLLOWING AMY'S TRAIL V. BEHIND THE PANEL VI. A HOLDUP VII. AN INVITATION TO LUNCH VIII. A BOLD MOVE IX. THE ROBBERY X. HANLEY CRON'S STUDIO XI. A VISITOR XII. THE MISSING WORKMAN XIII. AN EMBARRASSING INTERVIEW XIV. THE MYSTERIOUS AGENT XV. A PUZZLING LETTER XVI. WATCHFUL WAITING XVII. "PRIVATE--KEEP OUT" XVIII. CAPTURED XIX. FIRE! XX. THE SECRET REVEALED…
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