Gus pursed his lips. "Just before she . . . left Aztlan, Rosalita left a note for me. In it she said she had discovered something that could lead to what she called the ‘end of the world.’ She said that no one must ever learn the secret she had discovered. She was fearful because the cultists had contacted her—they seemed to sense that she knew something of value and was keeping it from them. She said it was only a matter of time before they made her tell."