"To assist you in every way possible--yes." "To leave me, if I am not able to go on; to take the letters and press on alone," she insisted, her eyes shining. "Promise me, my friend!" "I shall have to be governed by circumstances," said Stewart, cautiously. "If that seems the best thing to do--why, I'll do it, of course. But I warn you that this enterprise would soon go to pieces if it had no better wits than mine back of it. Why, in the few minutes they were searching you back there at the station, I walked straight into a trap--and with my eyes wide open, too--at the very moment when I was proudly thinking what a clever fellow I was!" "What was the trap?" she asked, quickly. "I was talking to that officer, and babbled out the story of how I came to go to the Kölner Hof, and he seemed surprised that a member of the police should have recommended it--which seems strange to me, too," he added, "now that I think of it. Then he asked me suddenly how you knew I was there." "Yes, yes; and what did you say?" "I didn't say anything for a minute--I felt as though I were falling out of a airship. But after I had fallen about a mile, I managed to say that I had sent you a telegram and also a postcard." "How lucky!" breathed the girl. "How shrewd of you!" "Shrewd? Was it? But that shock was nothing to the jolt I got the next minute when he told me that you had brought the postcard along in your bag! It was a good thing you came in just then, or he would have seen by the way I sat there gaping at him that the whole story was a lie!" "I should have told you of the postcard," she said, with a gesture of annoyance. "It is often just some such tiny oversight which wrecks a whole plan. One tries to foresee everything--to provide for everything--and then some little, little detail goes wrong, and the whole structure comes tumbling down. It was chance that saved us--but in affairs of this sort, nothing must be left to chance! If we had failed, it would have been my fault!" "But how could there have been a postcard?" demanded Stewart. "I should like to see it." Smiling, yet with a certain look of anxiety, she stepped to her bag, took out the postcard, and handed it to him. On one side was a picture of the cathedral at Cologne; on the other, the address and the message: Cologne, July 31, 1914. Dear Mary-- Do not forget that it is to-morrow, Saturday, you are to meet me at Aix-la-Chapelle, from where we will go on to Brussels together, as we have planned. If I should fail to meet you at the train, you will find me at a hotel called the Kölner Hof, not far from the station. With much love, BRADFORD STEWART. Stewart read this remarkable message with astonished eyes, then, holding the card close to the candle, he stared at it in bewilderment. "But it is my handwriting!" he protested. "At least, a fairly good imitation of it--and the signature is mine to a dot."