'Heaven only knows,' Mr Fields said.

After Nanny had aroused the children from sleep - by emitting a soft, musical whirr a few feet from their heads - she made certain that they were dressed and down at the breakfast table promptly, with faces clean and dispositions unclouded. If they were cross Nanny allowed them the pleasure of riding downstairs on her back.

Coveted pleasure! Almost like a roller coaster, with Bobby and Jean hanging on for dear life and Nanny flowing down step by step in the funny rolling way she had.

Nanny did not prepare breakfast, of course. That was all done by the kitchen. But she remained to see that the children ate properly and then, when breakfast was over, she supervised their preparations for school. And after they had got their books together and were all brushed and neat, her most important job: seeing that they were safe on the busy streets.

There were many hazards in the city, quite enough to keep Nanny watchful. The swift rocket cruisers that swept along, carrying businessmen to work. The time a bully had tried to hurt Bobby. One quick push from Nanny's starboard grapple and away he went, howling for all he was worth. And the time a drunk started talking to Jean, with heaven knows what what in mind. Nanny tipped him into the gutter with one nudge of her powerful metal side. in mind. Nanny tipped him into the gutter with one nudge of her powerful metal side.

Sometimes the children would linger in front of a store. Nanny would have to prod them gently, urging them on. Or if (as sometimes happened) the children were late to school, Nanny would put them on her back and fairly speed along the sidewalk, her treads buzzing and flapping at a great rate.

After school Nanny was with them constantly, supervising their play, watching over them, protecting them, and at last, when it began to get dark and late, dragging them away from their games and turned in the direction of home.

Sure enough, just as dinner was being set on the table, there was Nanny, herding Bobby and Jean in through the front door, clicking and whirring admonishingly at them. Just in time for dinner! A quick run to the bathroom to wash their faces and hands.

And at night- Mrs Fields was silent, frowning just a little. At night ... 'Tom?' she said.

Her husband looked up from his paper. 'What?'

'I've been meaning to talk to you about something. It's very odd, something I don't understand. Of course, I don't know anything about mechanical things. But Tom, at night when we're all sleep and the house is quiet, Nanny-'

There was a sound.

'Mommy!' Jean and Bobby came scampering into the living room, their faces flushed with pleasure. 'Mommy, we raced Nanny all the way home, and we won!'

'We won,' Bobby said. 'We beat her.'

'We ran a lot faster than she did,' Jean said.

'Where is Nanny, children?' Mrs Fields asked.

'She's coming. h.e.l.lo, Daddy.'

'h.e.l.lo, kids,' Tom Fields said. He c.o.c.ked his head to one side, listening. From the front porch came an odd sc.r.a.ping sound, an unusual whirr and sc.r.a.pe. He smiled.

'That's Nanny,' Bobby said.

And into the room came Nanny.

Mr Fields watched her. She had always intrigued him. The only sound in the room was her metal treads, sc.r.a.ping against the hardwood floor, a peculiar rhythmic sound. Nanny came to a halt in front of him, stopping a few feet away. Two unwinking photocell eyes appraised him, eyes on flexible wire stalks. The stalks moved speculatively, weaving slightly. Then they withdrew.

Nanny was built in the shape of a sphere, a large metal sphere, flattened on the bottom. Her surface had been sprayed with a dull green enamel, which had become chipped and gouged through wear. There was not much visible in addition to the eye stalks. The treads could not be seen. On each side of the hull was the outline of a door. From these the magnetic grapples came, when they were needed. The front of the hull came to a point, and there the metal was reinforced. The extra plates welded both fore and aft made her look almost like a weapon of war. A tank of some kind. Or a ship, a rounded metal ship that had come up on land. Or like an insect. A sowbug, as they are called.

'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 leg 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?'

'About her. About Nanny.'

'Why?'

'I - I don't know.'

'You mean we're going to have to repair her again? We just got through fixing her. What is it this time? If those kids didn't get her to-'

'It's not that.'

'What, then?'

For a long time his wife did not answer. Abruptly she got up from the table and walked across the room to the stairs. She peered up, staring into the darkness. Tom watched her, puzzled.

'What's the matter?'

'I want to be sure she can't hear us.'

'She? Nanny?'

Mary came toward him. 'Tom, I woke up last night again. Because of the sounds. I heard them again, the same sounds, the sounds I heard before. And you told me it didn't mean anything!'

Tom gestured. 'It doesn't. What does it mean?'

'I don't know. That's what worries me. But after we're all asleep she comes downstairs. She leaves their room. She slips down the stairs as quietly as she can, as soon as she's sure we're all asleep.'

'But why?'

'I don't know! Last night I heard her going down, slithering down the stairs, quiet as a mouse. I heard her moving around down here. And then-'

'Then what?'

'Tom, then I heard her go out the back door. Out, outside the house. She went into the back yard. That was all I heard for a while.'

Tom rubbed his jaw. 'Go on.'

'I listened. I sat up in bed. You were asleep, of course. Sound asleep. No use trying to wake you. I got up and went to the window. I lifted the shade and looked out. She was out there, out in the back yard.'

'What was she doing?'

'I don't know.' Mary Fields's face was lined with worry. 'I don't know! What in the world would would a Nanny be doing outside at night, in the back yard?' a Nanny be doing outside at night, in the back yard?'

It was dark. Terribly dark. But the infrared filter clicked into place, and the darkness vanished. The metal shape moved forward, easing through the kitchen, its treads halfretracted for greatest quiet. It came to the back door and halted, listening.

There was no sound. The house was still. They were all asleep upstairs. Sound asleep.

The Nanny pushed, and the back door opened. It moved out onto the porch, letting the door close gently behind it. The night air was thin and cold. And full of smells, all the strange, tingling smells of the night, when spring has begun to change into summer, when the ground is still moist and the hot July sun has not had a chance to kill all the little growing things.

The Nanny went down the steps, onto the cement path. Then it moved cautiously onto the lawn, the wet blades of gra.s.s slapping its sides. After a time it stopped, rising up on its back treads. Its front part jutted up into the air. Its eye stalks stretched, rigid and taut, waving very slightly. Then it settled back down and continued its motion forward.

It was just going around the peach tree, coming back toward the house, when the noise came.

It stopped instantly, alert. Its side doors fell away and its grapples ran out their full lengths, lithe and wary. On the other side of the board fence, beyond the row of shasta daisies, something had stirred. The Nanny peered, clicking filters rapidly. Only a few faint stars winked in the sky overhead. But it saw, and that was enough.

On the other side of the fence a second Nanny was moving, making its way softly through the flowers, coming toward the fence. It was trying to make as little noise as possible. Both Nannies stopped, suddenly unmoving, regarding each other - the green Nanny waiting in its own yard, the blue prowler that had been coming toward the fence.

The blue prowler was a larger Nanny, built to manage two young boys: Its sides were dented and warped from use, but its grapples were still strong and powerful. In addition to the usual reinforced plates across its nose there was a gouge of tough steel, a jutting jaw that was already sliding into position, ready and able.

Mecho-Products, its manufacturer, had lavished attention on this jaw-construction. It was their trademark, their unique feature. Their ads, their brochures, stressed the ma.s.sive frontal scoop mounted on all their models. And there was an optional a.s.sist: a cutting edge, power-driven, that at extra cost could easily be installed in their 'Luxury-line' models.

This blue Nanny was so equipped.

Moving cautiously ahead, the blue Nanny reached the fence. It stopped and carefully inspected the boards. They were thin and rotted, put up a long time ago. It pushed its hard head against the wood. The fence gave, splintering and ripping. At once the green Nanny rose on its back treads, its grapples leaping out. A fierce joy filled it, a bursting excitement. The wild frenzy of battle.

The two closed, rolling silently on the ground, their grapples locked. Neither made any noise, the blue Mecho-Products Nanny nor the smaller, lighter, pale-green Service Industries, Inc., Nanny. On and on they fought, hugged tightly together, the great jaw trying to push underneath, into the soft treads. And the green Nanny trying to hook its metal point into the eyes that gleamed fitfully against its side. The green Nanny had the disadvantage of being a medium-priced model; it was outcla.s.sed and outweighed. But it fought grimly, furiously.

On and on they struggled, rolling in the wet soil. Without sound of any kind. Performing the wrathful, ultimate task for which each had been designed.

'I can't imagine,' Mary Fields murmured, shaking her head. 'I just don't know.'

'Do you suppose some animal did it?' Tom conjectured. 'Are there any big dogs in the neighborhood?'

'No. There was a big red Irish setter, but they moved away, to the country. That was Mr Petty's dog.'

The two of them watched, troubled and disturbed. Nanny lay at rest by the bathroom door, watching Bobby to make sure he brushed his teeth. The green hull was twisted and bent. One eye had been shattered, the gla.s.s knocked out, splintered. One grapple no longer retracted completely; it hung forlornly out of its little door, dragging uselessly.

'I just don't understand,' Mary repeated. 'I'll call the repair place and see what they say. Tom, it must have happened sometime during the night. While we were asleep. The noises I heard-'

'Shhh,' Tom muttered warningly. Nanny was coming toward them, away from the bathroom. Clicking and whirring raggedly, she pa.s.sed them, a limping green tub of metal that emitted an unrhythmic, grating sound. Tom and Mary Fields unhappily watched her as she lumbered slowly into the living room.

'I wonder,' Mary murmured.

'Wonder what?'

'I wonder if this will happen again.' She glanced up suddenly at her husband, eyes full of worry. 'You know how the children love her ... and they need her so. They just wouldn't be safe without her. Would they?'

'Maybe it won't happen again,' Tom said soothingly. 'Maybe it was an accident.' But he didn't believe it; he knew better. What had happened was no accident.

From the garage he backed his surface cruiser, maneuvered it until its loading entrance was locked against the rear door of the house. It took only a moment to load the sagging, dented Nanny inside; within ten minutes he was on his way across town to the repair and maintenance department of Service Industries, Inc.

The serviceman, in grease-stained white overalls, met him at the entrance. 'Troubles?' he asked wearily; behind him, in the depths of the block-long building, stood rows of battered Nannies, in various stages of disa.s.sembly. 'What seems to be the matter this time?'

Tom said nothing. He ordered the Nanny out of the cruiser and waited while the serviceman examined it for himself.

Shaking his head, the serviceman crawled to his feet and wiped grease from his hands. 'That's going to run into money,' he said. 'The whole neural transmission's out.'

His throat dry, Tom demanded: 'Ever see anything like this before? It didn't break; you know that. It was demolished.'

'Sure,' the serviceman agreed tonelessly. 'It pretty much got taken down a peg. On the basis of those missing chunks-' He indicated the dented anterior hull-sections. 'I'd guess it was one of Mecho's new jaw-models.'

Tom Fields's blood stopped moving in his veins. 'Then this isn't new to you,' he said softly, his chest constricting. 'This goes on all the time.'

'Well, Mecho just put out that jaw-model. It's not half bad ... costs about twice what this model ran. Of course,' the serviceman added thoughtfully, 'we have an equivalent. We can match their best, and for less money.'

Keeping his voice as calm as possible, Tom said: 'I want this one fixed. I'm not getting another.'

'I'll do what I can. But it won't be the same as it was. The damage goes pretty deep. I'd advise you to trade it in - you can get d.a.m.n near what you paid. With the new models coming out in a month or so, the salesmen are eager as h.e.l.l to-'

'Let me get this straight.' Shakily, Tom Fields lit up a cigarette. 'You people really don't want to fix these, do you? You want to sell brand-new ones, when these break down.' He eyed the repairman intently. 'Break down, or are knocked knocked down.' down.'

The repairman shrugged. 'It seems like a waste of time to fix it up. It's going to get finished off, anyhow, soon.' He kicked the misshapen green hull with his boot. 'This model is around three years old. Mister, it's obsolete.'

'Fix it up,' Tom grated. He was beginning to see the whole picture; his self-control was about to snap. 'I'm not getting a new one! I want this one fixed!'

'Sure,' the serviceman said, resigned. He began making out a work-order sheet. 'We'll do our best. But don't expect miracles.'

While Tom Fields was jerkily signing his name to the sheet, two more damaged Nannies were brought into the repair building.

'When can I get it back?' he demanded.

'It'll take a couple of days,' the mechanic said, nodding toward the rows of semi-repaired Nannies behind him. 'As you can see,' he added leisurely, 'we're pretty well full-up.'

'I'll wait,' Tom said tautly. 'Even if it takes a month.'

'Let's go to the park!' Jean cried.

So they went to the park.

It was a lovely day, with the sun shining down hotly and the gra.s.s and flowers blowing in the wind. The two children strolled along the gravel path, breathing the warm-scented air, taking deep breaths and holding the presence of roses and hydrangeas and orange blossoms inside them as long as possible. They pa.s.sed through a swaying grove of dark, rich cedars. The ground was soft with mold underfoot, the velvet, moist fur of a living world beneath their feet. Beyond the cedars, where the sun returned and the blue sky flashed back into being, a great green lawn stretched out.