If he could remember! His mind came up sharply against leaving Irma and taking out the mail; then it went abruptly blank. What had been in the letter? It had been from a professor--it might have been from Professor Meinzer. That would tie in neatly. But Meinzer was dead, and he couldn't remember. They'd stripped him of his memory. How? Why? Were they trying to prevent his giving information to others--or were they trying to get something from him? And what could he know? He'd dabbled with ESP mathematically, but now he found himself wondering if it could exist. Could they be tracking him by some natural or mechanical ability to read his mind? He strained his own mind to find a whisper of foreign thought, outside his brain. He drew a blank, of course, as he'd expected. There were no answers. They could play with him, like a cat juggling a mouse, letting him almost learn something--and then, always, they arrived just in time to prevent his success! Put a rat in a maze where it can't learn the path, and it goes insane. But what good would he be to anyone if they drove him insane? And why bother with all that when they could silence him as well by killing him? He'd forgotten to watch, and was surprised to find his feet on the steps of the apartment building. He jerked back, and bumped into someone. "Sorry." The words came from behind him, automatically, and he turned to see the slim young man stepping aside. For a second, their eyes met squarely. A row of teeth flashed in a brief smile as the man started around him. "Guess I was thinking. Should have watched where I was going." The man went on down the street, and turned in at the restaurant entrance. * * * * * Hawkes lifted a foot that weighed a ton and slowly closed his mouth. He'd been facing away from the street light--and his face might have been hard to see. Yet.... It didn't fit. The young man must have known him! He blanked it from his mind. He couldn't believe that it was anything but lack of recognition. It was hard to see here, where the other was facing the light, and he was in the shadow. But it still meant that they were waiting, nearby. He dashed up the stairs, expecting a rush at both landings. The normal sounds of the apartment house went on. He listened at his door, but he could hear nothing except the same drip he had heard before. Slowly, he inserted the key and went in. The small bulb was still on. He crept along, trying to move silently on floors that insisted on creaking. The living room was as he had left it, and he caught sight of Ellen on the bed. He spotted a mirror over one of the dressers, and used that to study more of the bedroom. It seemed as empty as before.