"Come on!" Bobby shouted.

Abruptly Nanny moved, spinning slightly as her treads gripped the floor and turned her around. One of her side doors opened. A long metal rod shot out. Playfully, Nanny caught Bobby's arm with her grapple and drew him to her. She perched him on her back. Bobby's legs straddled the metal hull. He kicked with his heels excitedly, jumping up and down.

"Race you around the block!" Jean shouted. "Giddup!" Bobby cried. Nanny moved away, out of the room with him. A great round bug of whirring metal and relays, clicking photocells and tubes. Jean ran beside her. There was silence. The parents were alone again. "Isn't she amazing?" Mrs. Fields said. "Of course, robots are a common sight these days. Certainly more so than a few years ago. You see them everywhere you go, behind counters in stores, driving buses, digging ditches—"

"But Nanny is different," Tom Fields murmured.

"She's—she's not like a machine. She's like a person. A living person. But after all, she's much more complex than any other kind. She has to be. They say she's even more intricate than the kitchen."

"We certainly paid enough for her," Tom said.

"Yes," Mary Fields murmured. "She's very much like a living creature." There was a strange note in her voice. "Very much so."

"She sure takes care of the kids," Tom said, returning to his newspaper.

"But I'm worried." Mary put her coffee cup down, frowning. They were eating dinner. It was late. The two children had been sent up to bed. Mary touched her mouth with her napkin. "Tom, I'm worried. I wish you'd listen to me."

Tom Fields blinked. "Worried? What about?"