In his excitement he rested the stock of his rifle upon the floor and bent upon Billie a gaze so fierce as greatly to disconcert him for the moment. But Billie was not a lad to be easily unnerved and after a moment he replied calmly: "I call you by the only name I know. It was the one you used on the Rio Grande when you sent me on a mission to Pancho Villa." "Villa! Villa!" repeated Santiago, as though trying to recall something that had passed from his memory. "Villa! Where have I heard that name before?" "On the Rio Grande is all I can tell you. Do you remember Don Rafael?" At mention of the name the expression on Santiago's face changed again, this time to one of fiercest rage. "Don Rafael!" he cried. "Don Rafael! Now I know you! You are Don Rafael. That is why I should kill you!" "Great Scott, no, I am not Don Rafael!" shouted Billie as Santiago again raised his rifle and the lad perceived that he had to do with a crazy man. "I'm the boy that saved your life when Don Rafael tried to kill you. Don't you remember?" Again Santiago lowered his weapon, and again there came upon his face that puzzled expression. "Tell me, Santiago--I mean Prince Iztazil, or whatever you call it, what are you doing here?" Santiago eyed him suspiciously, but finally laid his rifle across a table in the center of the room and approached nearer the lad. "Listen!" he said in a whisper. "I am the guardian of the treasure of Montezuma. It is to be used to free Mexico from the Spaniard. He must be driven out. The land belongs to the Aztec." "But where is the Aztec?" queried Billie. "I know him not." "I am he. The peons are my people. The Spaniard--bah! He owns the houses and he owns the lands; but he must be driven out." "Isn't that what Villa says?" "Villa? Villa?" again repeated Santiago, and again he lapsed into silence. For some minutes he remained motionless ere he stepped back, picked up his rifle and started for a door leading to a stairway. "Come!" he commanded. "I will show you." "Hadn't we better take care of the horse first?" asked Billie, not at all anxious to be wandering around with an armed lunatic. "He may die." "What is a horse when the future of Mexico is at stake, my son? Come with me and you shall hear a strange tale." "I have heard one already," was Billie's mental comment, but realizing by the term son which Santiago had applied to him that he was in no immediate danger and trusting to his wits to finally overcome the strange man should it become necessary, he followed. At the head of the stairs was another door, which Santiago opened and entered. It was a sort of ante-room, much like the entrance into a lodge room. Around the walls was a motley collection of firearms, swords, spears and smaller weapons. Stopping in front of one of the racks, Santiago placed his rifle in it, and then from another took a couple of small swords, one of which he handed to Billie.