"That's all right, old man," laughed the corporal. "You know you would not go home if you could." "Better not give me a chance," was the grumbling reply, as the trooper bit off a big piece of tobacco and tucked it away in his cheek. Reveille was just sounding when the boys, accompanied by their three friends and Ambrosio, perched upon Billie's horse, drew up in front of Lieut. Grant's quarters. They had been recognized and passed through the lines, and as the men caught sight of them they were given a hearty cheer. "You seem to have made friends," laughed the lieutenant as he greeted them, "and there is every reason why you should. The general will be glad to see you and hear your report. I have no doubt you have a good story to tell, and he likes a good story." When the boys reached home they found the gate still locked, although it was now considerably past the time when the household was astir. Their knock was answered by the _portero_, who, in response to a question by Billie, said that Santiago was seriously ill and had been for thirty-six hours. "What is the matter?" asked Donald. "Fever." "I am not surprised," declared Adrian. "The strange thoughts he has been thinking so many days were bound to result in something serious." "Perhaps it is not convenient for us to remain here," said Mr. Black. "We can, I am sure, find some other place." But at this moment Lucia appeared at the head of the stairs. When made acquainted with Mr. Black's words she would not hear of his taking Josie to any other house and gave orders for making her perfectly at home. The only one who did not remain was Strong. "I'll come back this evening," he said. "I have a strange story to tell you boys and I may need your help in locating a man I am most anxious to find." But he did not come back that evening, and when he did come the next night the boys were not there, having been invited to dine with Gen. Funston. Had things not happened thus, a part of this story could never have been written, for it was while dining with the general that the boys were given a duty to perform, which was the most arduous of all their adventures in the land of the Montezumas. And this was the manner of it. They were just finishing dinner and Billie was congratulating himself that he had had his fill of good American cooking, when an aide announced that a Mexican gentleman, Don Esteban Mendoza, craved an immediate audience with Gen. Funston. "I am sure you young gentlemen will excuse me a few minutes," said the general, "as Don Esteban is one of the prominent bankers of the city and I know his business must be of importance." The boys were glad to accept the proffered excuse and the general withdrew, leaving them in the company of several members of his staff, to whom they briefly related their recent adventure. When they told of the "ambush" there was much amusement. In the midst of their conversation the general returned accompanied by Don Esteban.