Ackerman sat down and put his face in his hands. "I don't know," he said soberly. "It seems that I am to make a choice between worlds. I can save one but not the other."

As Ackerman sat there, face lowered and spirits lower, he was in complete misery and totally oblivious to everything about him. One thing only penetrated the depth of his introversion.

That one thing was the cool touch of a soft hand on his shoulder. There was a delicate scent—one that brought memories, both delicately fond and angrily disconcerting. Tansie Lee seated herself beside him and put an arm over his shoulder. "Don't do that to him," she said, speaking to her husband with pleading.

"I can't live his life," he answered; "one more thing, and he'll be all right."

Ackerman looked from one to the other, puzzled. Had he been the other man, he would have been consumed with jealousy. "What?" he asked weakly.

"I can't tell you completely," said the other, "but it has to do with the 'time-fission' and the temperon; you'll figure it out."

There came to Ackerman that he did have the answer. The way to solve the problem was to use his ability to remove the temperon from the cyclotron, and thus avert the explosion!

Tansie stood up. "Come on, Les," she said to him.

"Come on?" he asked dully.