He felt the box all over, but could find nothing. Then he closed it and set it upon the table. A moment later Donald picked it up and tried to open it, but it was locked fast. "Nothing but mysteries," he said. "I'm getting tired of them. But before anything else happens, I'm going around and notify Don Esteban that the box is here." "I'll go with you," said Adrian. "No, you'd better stay here. I'll take a mozo with me." He ran hastily down the stairs and a minute later the boys heard the gate close behind him. "I guess this is the quickest way," thought Donald as he gained the sidewalk. "I'll not bother with a mozo. With American soldiers on guard and my automatic in my pocket, I have nothing to fear." A couple of minutes later he was ringing the bell at Don Esteban's house. He was hastily admitted and at once conducted to that gentleman's presence, where he narrated hastily what had occurred at the other house. "Who is this old man?" Don Esteban asked of Donald. Donald explained as best he could. "Which is mighty little," he declared when he had finished. "He is the greatest mystery we have ever encountered. There is no doubt that he is an Indian, but he speaks English like an Englishman." "I must go and see him at once," declared Don Esteban, rising. "I don't think you can, sir, to-night. I don't think the physician would permit it." "Well, then, the first thing in the morning. I thank you, young sir. Won't you have a glass of wine before you go?" "No, I think not," replied Donald. "I've never acquired that Mexican habit yet. Good night, sir." He left the house feeling greatly relieved that he had reported the finding of the box and walked slowly along whistling merrily. As he turned off the street upon which Don Esteban lived he heard soft footsteps behind him and turned hastily. But he was too late. Before he could see who it was, or ere he could cry out, a cloak was thrown over his head and he was picked up and carried away bodily. Donald was not the boy to give in without a struggle, but kick and squirm as he might, he could not free himself. Presently those who were carrying him stopped and laid him on the sidewalk. Then he heard a knock and a gate opened. Then he was lifted up again and, almost before he knew it, he was thrust into a little room--a closet it seemed--and the door closed upon him. It was a hot night and the little place was stifling. "I'll smother if I don't get out of this," he muttered. Slowly he unwrapped the cloak from about his head and at last freed himself completely from its folds; but he secured little relief from the heat. The room could not have been more than six feet square and it did not take Donald long to run his hand clear around the wall. There was only one door, that through which he had been thrust, and it was locked. He pounded upon it, but to no avail. Then he sat down to think.