This aimless wandering finally brought her to the Rhine, and eventually Grace sank down on a bench and began studying her German grammar. She saw the captain approaching, but did not look up, for there were many persons, German and American, strolling along, enjoying the view. Doughboys arm in arm with rosy-cheeked frauleins passed and repassed, prospective war brides, many of them; women going to the river to wash their rough clothing, and dignified Germans with chins elevated, marching back and forth with a suggestion of the goose-step in their stride. The captain was nearly past her, when he appeared suddenly to have discovered the Overton girl. He halted and saluted. “Why, good morning, Mrs. Gray,” he exclaimed. “You must be a late riser, sir,” chided Grace. “It is now well into the afternoon. Won’t you sit down, if I may be so bold as to ask an officer to sit down beside me?” The conversation had been carried on in tones loud enough to be heard by any one passing. “There is a man down near the water’s edge who appears to be interested in us. I would suggest that we seem to be indulging only in airy persiflage,” suggested the Overton girl, raising her voice in a merry laugh, the captain bowing and smiling to keep up the illusion. Grace opened her German book and pointed to the page, speaking in a low tone. “I observe that the mouse walked into the trap,” she said. “What mouse do you refer to?” “The mouse that is now on his way to a certain building near Paris known as the American prison.” Grace laughed merrily. “Yat Sen! How did you know?” “Got it out of the air, sir.” “Thanks to you we caught him. The screws in the hinges of the cellar window, we discovered in advance, had been loosened so that all one had to do was to pull the window out. There was no short-circuit about this affair. The man crept in and actually started a fire in the rubbish down there. The men we had planted there pounced upon him, but they had a time getting the fire out without calling for assistance, which we did not wish them to do. We tried to make him confess.” “A waste of time,” observed Grace. “Yes. Chinamen lose the power of speech absolutely when you try to drag information from them. The situation is really serious. It is those back of such cut-throats as Yat Sen that we wish to get. You have done a very great service to us, but you began at the wrong end. It isn’t the little man that we are after, it is the head and brains of the plot against the Army of Occupation.” “I think it can be arranged to put that information into your hands too, sir.” “If you can do that you ought to be promoted to the rank of General. You have discovered something! Gordon said you would. Tell me. We mustn’t sit here long.” They were keeping up a semblance of merry chatter through the conversation. “You know where we are living, Captain?” “Yes.”