Yes, there was no mistaking him. He was the right man. Each of them knew by heart the creases on his stout face and the sweep of his gray moustache. But there was nothing noticeable in a boy looking for a moment at a piece of paper, and Marco sauntered a few steps to a bit of space left bare by the crowd and took a last glance at his sketch. His rule was to make sure at the final moment. The music was very good and the group about the carriage was evidently enthusiastic. There was talk and praise and comment, and the old aristocrat nodded his head repeatedly in applause. "The Chancellor is music mad," a looker-on near the boys said to another. "At the opera every night unless serious affairs keep him away! There you may see him nodding his old head and bursting his gloves with applauding when a good thing is done. He ought to have led an orchestra or played a 'cello. He is too big for first violin." There was a group about the carriage to the last, when the music came to an end and it drove away. There had been no possible opportunity of passing close to it even had the presence of the young officer and the boy not presented an insurmountable obstacle. Marco and The Rat went on their way and passed by the Hof-Theater and read the bills. "Tristan and Isolde" was to be presented at night and a great singer would sing _Isolde_. "He will go to hear that," both boys said at once. "He will be sure to go." It was decided between them that Marco should go on his quest alone when night came. One boy who hung around the entrance of the Opera would be observed less than two. "People notice crutches more than they notice legs," The Rat said. "I'd better keep out of the way unless you need me. My time hasn't come yet. Even if it doesn't come at all I've--I've been on duty. I've gone with you and I've been ready--that's what an aide-de-camp does." He stayed at home and read such English papers as he could lay hands on and he drew plans and re-fought battles on paper. Marco went to the opera. Even if he had not known his way to the square near the place where the Hof-Theater stood, he could easily have found it by following the groups of people in the streets who all seemed walking in one direction. There were students in their odd caps walking three or four abreast, there were young couples and older ones, and here and there whole families; there were soldiers of all ages, officers and privates; and, when talk was to be heard in passing, it was always talk about music. For some time Marco waited in the square and watched the carriages roll up and pass under the huge pillared portico to deposit their contents at the entrance and at once drive away in orderly sequence. He must make sure that the grand carriage with the green and silver liveries rolled up with the rest. If it came, he would buy a cheap ticket and go inside.