“What! Aren’t they with you?” exclaimed Alan, peering through the gloom. “Where on earth have you fellows been all night? I got as nervous as a girl thinking that something might have happened to you.”

“Well,” drawled Buck, enjoying Alan’s impatient curiosity, “we did bump into a little adventure.”

Then he went on to give Alan the details of their chance discovery of the plot to assassinate the aged Emperor Franz Joseph on the following evening.

“Bob followed one man, Ned another, and I the third—a gigantic chap who could almost pulverize me with a single blow. I followed him about for an hour or more, going to first one low dive and then to another, but always in the poorer, more squalid sections of the city where there were few street lamps and where the second stories of ramshackle old houses nearly met overhead. The smells were awful, and every street corner had its individual knot of evil-looking loafers being harangued by wild-eyed, long-haired chaps, looking as if they would cut one’s throat for a nickel. Each demagogue was working his little gang of listeners up to a point of frenzy. Some of the orators were preaching socialism, others a reversion to pious living. Some waved their arms in an impassioned plea for absolute anarchy; still others stood on old soap boxes, with thin lips that alternately sneered or snarled, preaching atheism, revolution, murder.

“You may well believe that I wasn’t at all at ease passing through throngs of that sort all the while and having to stop every now and then because Black-beard’s taxi did, while he leaned out of the window to note the attitude of the rabble. Once in a while he would be recognized by persons loitering in the street-corner aggregations. Several times men sidled slyly up to his taxicab and seemed to be making reports or getting fresh instructions from him.

“I followed my man around that way for more than two hours without anything in particular happening, and finally trailed him to bed at a middle-class boarding house in the Neyban district. Then I came on back here.”

The last words were hardly out of his mouth before Bob Russell joined them, his manner triumphant.

“Hello, boys!” cried he. “I don’t know what luck you may have had, but I ran my little fat man to ground and have found out enough about him to hang him higher than Haman.”

“Tell us about it,” both boys said.

Bob continued: