ContentsI. [WHAT CAME OF HENRY'S IDEA]II. [HENRY OVERCOMES AN OBSTACLE]III. [THE WIRELESS PATROL PREPARES FOR ACTION]IV. [THE SCENE OF ACTION]V. [THE MESSAGE IN CIPHER]VI. [A NEW DANGER POINT]VII. [CONFUSION WORSE CONFOUNDED]VIII. [WHERE MONEY TALKED]IX. [A FRESH START]X. [THE PURSUIT IN THE DARK]XI. [AN UNSUCCESSFUL SEARCH]XII. [ANOTHER OBSTACLE]XIII. [WHAT HENRY DISCOVERED]XIV. [THE RIDDLE SOLVED]XV. [ANOTHER MYSTERY UNRAVELED]XVI. [AN UNEXPECTED MESSAGE]XVII. [A CHANGE IN CIPHERS]XVIII. [TOO LATE]XIX. [THE ENEMY ESCAPES]XX. [A CLUE FROM THE AIR]XXI. [THE CAPTURE OF THE SPIES]XXII. [A TASK ACCOMPLISHED]