The look of the millionaire became a stare, and his hand shook as he laid it upon the desk before him. “Come!” cried Opal. “Must we really buy your silence?” “It is not in the market, miss, as I have once told you. I want to reach the solution of this terrible crime. I shall not turn from the trail till I am at the end of it. Mother Flintstone’s blood calls for revenge, and----” Opal, who stood beside her father, leaned over him and whispered in his ear. The old man’s face brightened. “Not another word till I come back,” continued the girl to her parent, and with this she left the room. Two minutes later her steps were heard at the door across the room and once more she stood before Nick. In that short time she had gowned herself for the street, and, stepping to one side, she touched a button. “We are going out,” said she, looking at the detective. “I have just ordered the carriage.” The detective looked amazed. Going out with that girl? The turn of affairs actually amused him. “I want you to accompany me to a certain place,” continued Opal Lamont. “We shall not be there long; but you must go with me.” The detective consented, and in a few moments they entered the carriage which had come to the front door. Opal had drawn a spotted veil over her face and had fallen back into the depths of the vehicle saying nothing, although addressed by the detective. The coachman seemed to know where to go. Carter had not heard the girl give him any orders, but he turned corner after corner, as if his destination was plain to him. For at least ten minutes the vehicle bounced over the stones, and then it halted in front of a two-story brick house in the lower part of Gotham. The detective looked out, and took in the contour of the house, and Opal opened the door of the cab. “We’re here,” she said, speaking for the first time since leaving home, and in a moment she dismounted, to be followed by the nonplused detective. The millionaire’s daughter led the way up the steps, and with a key opened the front door. As she threw it back she motioned to the detective to enter, and Carter soon stood in a fireless parlor darkened by heavy curtains at the windows. “I’ll see you in a moment,” said Opal, rushing toward the door, and the detective heard the sound of leather and silk on the stairs. “This is a queer adventure,” thought Carter. “This must be one of the many houses Perry Lamont owns. The young woman is a cool-headed thing and seems to have the nerves her father has lost. Why has she brought me to this place? What new mystery is this? Ah! here she comes!” There were footsteps in the hall, and the detective watched the door. But the sounds did not seem to come all the way down the flight; they appeared to stop midway, and the detective glanced up at the open transom. The sight he saw there riveted him to the spot. Leaning over the banisters was Opal Lamont, but how changed.