A moment more and Dixie Mason's little car was speeding toward Fifth Avenue, defying all law in general and policemen in particular in her mad haste to reach the house Von Papen had entered. She slowed down at the corner where she had stopped before and pointed to the house. She spoke in a low voice and directed her speech at Stewart. "In that house there, they are working the wireless!" Grant jumped to the sidewalk. He gave his directions in low tones. Dixie watched them seek for admittance at the door. She watched them open the iron barred gate and then with a splintering crash force their way into the house. She saw the butler that blocked their path fall under someone's heavy blow. And then they disappeared into the darkness of the gloomy reception hall. Grant and his men strode to the panelled doorway opening into the great room in which Dr. Albert received his guests and where the conferences of the German plotters were held. From behind the heavy doors came the crackle and splutter of a wireless apparatus. Under the strength of the three men the doors burst inward. Inside of the room, two men working the wireless rushed vainly toward the French windows for escape, only to find themselves pinioned and helpless in the handcuffs slipped on them by Grant and his operatives. Cavanaugh and Stewart soon dismantled the wireless equipment and put out of commission forever one of Germany's most dangerous weapons in America, but Grant watching them knew that it was but one of many and that for every blow thus dealt a dozen plots would spring up elsewhere. While this evil festered in their midst the eyes of the Secret Service must never close. He left the operatives on guard and turned toward the street with his captives. "Good man--that fellow who brought us here," he mused as they stepped out on the stone doorstep. "He's worth a special report to the Chief. If it hadn't been for him--" He stopped. Where the racer with its hooded, gauntletted driver had been was vacancy! His mysterious informant was gone! CHAPTER VIII THE KAISER'S DEATH MESSENGER--ROBERT FAY