In company with Lieutenant Gordon, of the United States Secret Service, and Frank Shaw, a member of the Black Bear Patrol, whose arrival was momentarily expected, the boys present had, on the previous day, returned from a series of unusual and exciting experiences in Mexico, and now they were discussing a proposed plan for an excursion to the Canal Zone. Of course they could make the trip if they desired, but what they wanted was to go in the company of Lieutenant Gordon, sent there on a secret mission by the Secretary of War.