She drew her cap down and adjusted her goggles more firmly as Von Papen advanced. "We've had an accident here," he said, "I've got to get back to town. Can you take me?" Dixie nodded and opened the door. Von Papen stepped in and gave her directions as to where he wished her to drive him--little knowing that he was giving information to the woman representative of the Secret Service! "Turn into Fifth Avenue at Fifty-second Street and then start up-town. Make it as fast as the law allows!" Captain Von Papen was snapping his orders excitedly, but in a low voice. "I've got to get there to notify the mother of the boy who has just been hurt. Understand?" Dixie nodded. Her foot pressed the accelerator. A moment more and the finger of the speedometer climbed to forty miles, then fifty and slowly to sixty where it stayed until the outlines of the city began to show against the western sky. Then Dixie slowed down to a speed which would allow her to pass the policemen they began to encounter at intervals without interference. She crossed over to Madison Avenue, and there slowed down. Von Papen glanced out and around the machine nervously. Evidently the way was clear, for he reached into his pocket and drew out a bill which he pressed into the driver's hand. "Drive on, please, no need to wait for me," he called, hurrying to the sidewalk. Dixie nodded and started the machine. She crossed Fifth Avenue. Just beyond the corner she stopped the car and jumped out. Scurrying to the corner she watched Von Papen enter the house. It was Dr. Albert's house, the huge Fifth Avenue mansion that German efficiency had turned into a spies' nest from which to prey upon a country with which it claimed to be on friendly terms and by whom it was trusted. Dixie Mason glanced up at its close curtained windows. Somewhere inside was Von Papen, gone there on an errand unknown to her but which she knew had some bearing on the events of the afternoon. What was his mission? In a moment the answer was given her. High up on the roof the slender antennae of a wireless outfit was being raised. Higher and higher with slim tentacles spreading as the machinery inside that controlled it was operated. There was no need for conjecture now. Dixie Mason knew the meaning of Von Papen's mad rush to reach this house. It was to reach another wireless depot from which messages could be caught and stopped. And she had been the means of assisting him to his purpose! Dixie Mason turned and ran to her car. A moment later she was breaking all traffic regulations as she sped toward the Criminology Club with one idea in mind--to reach Harrison Grant.