It was November when he first hit Mexico City. It was nearly the middle of April before he picked up anything at all worth while. Of course, in the meantime he had uncovered a number of leads--but every one of them was blind. For a day or two, or a week at most, they would hold out glowing promise of something big just around the corner. Then, when he got to the end of the rainbow, he would find an empty pail in place of the pot of gold he had hoped for. It wasn't surprising, therefore, that Stewart was growing tired of the life of continual mystery, of developments that never developed, of secrets that were empty and surprises that faded away into nothing. It was on the 13th of April, while seated at a little table in front of a sidewalk cafe on the Calles de Victoria, that the American agent obtained his first real clue to the impending disaster. When two Mexicans whom he knew by sight, but not by name, sat down at a table near his he pricked up his ears purely by instinct, rather than through any real hope of obtaining information of value. The arrival of the usual sugared drinks was followed by a few words of guarded conversation, and then one of the Mexicans remarked, in a tone a trifle louder than necessary, that "the United States is a nation of cowardly women, dollar worshipers who are afraid to fight, and braggarts who would not dare to back up their threats." It was an effort for Stewart to remain immersed in the newspaper propped up in front of him. Often as he had heard these sentiments expressed, his Southern blood still rose involuntarily--until his logic reminded him that his mission was not to start a quarrel, but to end one. He knew that no good could ensue from his taking up the challenge, and the very fact that the speaker had raised his voice gave him the tip that the words were uttered for his especial benefit, to find out whether he understood Spanish--for he made no attempt to disguise his nationality. With a smile which did not show on his lips, Stewart summoned the waiter and in atrocious Spanish ordered another glass of lemonade. His complete knowledge of the language was the one thing which he had managed to keep entirely under cover ever since reaching Mexico, for he figured that the natives would speak more freely in his presence if they believed he could not gather what they were discussing. The trick worked to perfection. "Pig-headed Yankee," commented the Mexican who had first spoken. "Lemonade! Pah!--they haven't the nerve to take a man's drink!" and he drained his glass of _pulque_ at a single gulp. The other, who had not spoken above a whisper, raised his glass and regarded it in silence for a moment. Then--"Prosit," he said, and drank. "_Nom di Dio_," warned his companion. "Be careful! The American hog does not speak Spanish well enough to understand those who use it fluently, but he may speak German."