"Yes ... what—was it?"
"Just this: Can Earth and Air mix? There's a legend in my time that few people understand, but I think I understand it. It's the story of Lilith, queen of Air and Darkness. She fought with Satan and God alike for the Earth, but she lost, because she was not part of their universe. It's the same with me. What part could I play in a time not my own, among people who live in the air?"
The girl did not move or answer. Steadily he went on: "Besides—there's a gap between us greater than parsecs or centuries. Look." He took her hand in his, held it up. The delicate, four-fingered limb made his own five stubby fingers look lumpy and misshapen. "We have no future together, Jina. We seem alike, but we're not. The apes are my cousins; the bats are yours. You should stay with your own race, and have the children I could never give you. We have no real happiness to give each other."
She drew back and squared her shoulders proudly, though her eyes still brimmed with tears. "You are right," she said. "Go back, then! But I extract one promise before you go."
He inclined his head. "Whatever I can do."
"You have the time-coil, and can visit any age you wish. Promise me—that you'll never come to this one again."
He said softly, "I promise, Jina."
Her first soft kiss was her last. The next instant, it was as if she had never been.
"Ready, Ken?"
The time-coil throbbed once, and then the glass-walled chamber was empty in the red sunlight.