That was the way the marak worked. There was nothing mysterious about the craving. It was simply that once you had experienced how delightful it was, you wouldn't do without it. The tablet he had taken that morning was losing its effect, but he felt so pleased at what he was doing that he didn't mind even that. For the next half hour he would enjoy himself simply by looking at Louise, and thinking that now at last they would be united again, no longer kept apart by her silly ideas about doing something to save themselves. And then the drug would take effect, and they would feel themselves lifted to the stars together, never to come down to this substitute for Earth again until the beam failed, and they went out together to make the repairs, and the shadows closed in on them. He had made sure that Louise had her back to him when he dropped the tablet into her glass, and he saw that she suspected nothing. She drank her wine, he noticed, without even commenting on the taste. He felt a sudden impulse to kiss her, and, somewhat to her surprise, he did so. Then he sat down again and went on with the dinner. He waited. An hour later he knew that he had made her happy. She was laughing as she hadn't laughed for a long time. She laughed at the humorous things he said, at the flattering way he raised his glass to her, even at what she saw through the window. Sometimes it seemed to him that she was laughing at nothing at all. He tried to think of how he had reacted the first time he had taken the drug. He hadn't been quite so aggressively cheerful, not quite so--hysterical. But then, the drug didn't have exactly the same effect on everyone. She wasn't as well balanced as he had been. The important thing was that she was happy. Curiously enough, he himself wasn't happy at all. It took about five seconds for the thought to become clear to him, five seconds in which he passed from dull amazement to an enraged and horrified comprehension. He sprang to his feet, overturning the table at which they still sat. And he saw that she wasn't surprised at all, that she still stared at him with a secret satisfaction. "You've cured me!" he cried. "You've fed me the antidote!" And he began to curse. He remembered the other time she had tried it, the time when he had been on the alert, and had easily detected the strange metallic taste of the stuff. He had spat it out, and under the influence of the drug from which she had hoped to save him, he had laughed at her. Now he was unable to laugh. He had been so intent on feeding the tablet to her that he had forgotten to guard himself, and he had been caught. He was normal now--her idea of being normal--and he would never again know the wonderful feeling the drug gave. He began to realize his situation on this horrible lonely asteroid. He cast a glance at the window and at what must be waiting outside, and it was his turn to shudder. He noticed that she was still smiling.