"Now," he said, "I want your promises not to try to escape." "Sorry, sir, but we can't do that," replied Frank, quietly. "Come! Don't be fools!" exclaimed their captor, sharply. He walked to the door and peered out. Then, walking close to Frank and Jack, he said quietly: "If you will give me your promises to make no attempt to escape before tomorrow night, I shall not have you guarded." Both lads started back in surprise, for the man had spoken in English and without the trace of an accent. "Great Scott!" exclaimed Frank. "You must be an Englishman." The man laid a finger to his lips. "Sh-h-h!" he warned. "Walls have ears, you know. So you don't know me?" The lads gazed at him closely. "I know I have seen you some place," declared Jack. "So have I," said Frank. "And to think that they don't know me," said the man, half to himself. Then he addressed them again. "I guess it is as well that you have not recognized me, but did I not know you so well I would not say what I am about to say. That is this. I am an Englishman and I am here on an important business. Tomorrow night I shall return to England. Give me your words to remain quiet here until then, in the meantime not trying to learn my identity, and you shall all go with me. Is it a bargain?" Frank looked at the man sharply. Was he fooling them? Well, the lad decided, they had everything to gain and nothing to lose. "Very well," the lad said. "You have my promise not to attempt to escape before tomorrow night." "And mine," said Jack. "And mine," declared Harris. "Very well. Then I shall leave you for the moment." The man stalked from the room and closed the door behind him. CHAPTER XXIV THE BOYS BECOME UNEASY For some moments after the officer had taken his departure, there was silence in the room. Then Harris exclaimed: "Now what do you think of that?" "Well, I don't hardly know what to think of it," Jack replied. "Frank took most of the talking on himself. When he gave his parole there was nothing left for me but to do likewise." "That's what I thought. Otherwise I wouldn't have given mine," said Harris. "It may not be too late to call him back and tell him so," said Frank. "I did the talking because neither of you seemed to want to do it. You didn't have to give your parole unless you wanted to. I didn't ask you to do it." "Come now, don't get mad, Frank," said Jack. "I'm not mad. I'm just telling you what I think. Certainly it can do us no harm. We have everything to gain and nothing to lose." "That's so, too, when you stop to think of it," Harris agreed. "Well, I stopped to think of it," said Frank. "You fellows didn't. That's the difference." "But who on earth can he be?" exclaimed Harris. "He seems to know you two, all right." "There is something strangely familiar about him," said Frank, "but I can't place him." "Nor I," admitted Jack, "though, as you say, there is something familiar about him."