The car swung up before him, the door springing open automatically. He had one foot on the running board before he saw the trap, saw the tight yellowish face and the glittering eyes inside the cab. Suddenly there was an explosion of bright purple brilliance, and he was screaming, twisting and screaming and reeling backward onto the sidewalk, doubled over with the agonizing fire that burned through his side and down one leg, forcing scream after scream from his throat as he blindly staggered to the wall of the building, pounded it with his fists for relief from the searing pain. And then he was on his side on the sidewalk, sobbing, blubbering incoherently to the uniformed policeman who was dragging him gently to his feet, seeing through burning eyes the group of curious people gathering around. Suddenly realization dawned through the pain, and he let out a cry of anger and bolted for the curb, knocking the policeman aside, his eyes wild, searching the receding stream of traffic for the cab, a picture of the occupant burned indelibly into his mind, a face he had seen, recognized. The cab was gone, he knew, gone like a breath of wind. The briefcase was also gone-- * * * * * He gave the address of the Essex University Hospital to the cabby, and settled back in the seat, gripping the hand-guard tightly to fight down the returning pain in his side and leg. His mind was whirling, fighting in a welter of confusion, trying to find some avenue of approach, some way to make sense of the mess. The face in the cab recurred again and again before his eyes, the gaunt, putty-colored cheeks, the sharp glittering eyes. His acquaintance with Frank Mariel had been brief and unpleasant, in the past, but that was a face he would never forget. But how could Mariel have known where he would be, and when? There was precision in that attack, far too smooth precision ever to have been left to chance, or even to independent planning. His mind skirted the obvious a dozen times, and each time rejected it angrily. Finally he knew he could no longer reject the thought, the only possible answer. Mariel had known where he would be, and at what time. Therefore, someone must have told him. He stiffened in the seat, the pain momentarily forgotten. Only one person could have told Mariel. Only one person knew where the file was, and where it would be after he left the restaurant--he felt cold bitterness creep down his spine. She had known, and sat there making eyes at him, and telling him how wonderful he was, how she was with him no matter what happened--and she'd already sold him down the river. He shook his head angrily, trying to keep his thoughts on a rational plane. _Why?_ Why had she strung him along, why had she even started to help him? And why, above all, turn against her own father?