Behind them Nanny came, trudging slowly, her treads clicking noisily. The dragging grapple had been repaired, and a new optic unit had been installed in place of the damaged one. But the smooth coordination of the old days was lacking; and the clean-cut lines of her hull had not been restored. Occasionally she halted, and the two children halted, too, waiting impatiently for her to catch up with them.

'What's the matter, Nanny?' Bobby asked her.

'Something's wrong with her,' Jean complained. 'She's been all funny since last Wednesday. Real slow and funny. And she was gone, for a while.'

'She was in the repair shop,' Bobby announced. 'I guess she got sort of tired. She's old, Daddy says. I heard him and Mommy talking.'

A little sadly they continued on, with Nanny painfully following. Now they had come to benches placed here and there on the lawn, with people languidly dozing in the sun. On the gra.s.s lay a young man, a newspaper over his face, his coat rolled up under his head. They crossed carefully around him, so as not to step on him.

'There's the lake!' Jean shouted, her spirits returning.

The great field of gra.s.s sloped gradually down, lower and lower. At the far end, the lowest end, lay a path, a gravel trail, and beyond that, a blue lake. The two children scampered excitedly, filled with antic.i.p.ation. They hurried faster and faster down the carefully graded slope, Nanny struggling miserably to keep up with them.

'The lake!'

'Last one there's a dead Martian stinko-bug!'

Breathlessly, they rushed across the path, onto the tiny strip of green bank against which the water lapped. Bobby threw himself down on his hands and knees, laughing and panting and peering down into the water. Jean settled down beside him, smoothing her dress tidily into place. Deep in the cloudy-blue water some tadpoles and minnows moved, minute artificial fish too small to catch.

At one end of the lake some children were floating boats with flapping white sails. At a bench a fat man sat laboriously reading a book, a pipe jammed in his mouth. A young man and woman strolled along the edge of the lake together, arm in arm, intent on each other, oblivious of the world around them.

'I wish we had a boat,' Bobby said wistfully.

Grinding and clashing, Nanny managed to make her way across the path and up to them. She stopped, settling down, retracting her treads. She did not stir. One eye, the good eye, reflected the sunlight. The other had not been synchronized; it gaped with futile emptiness. She had managed to shift most of her weight on her less-damaged side, but her motion was bad and uneven, and slow. There was a smell about her, an odor of burning oil and friction.

Jean studied her. Faintly she patted the bent green side sympathetically. 'Poor Nanny! What did you do, Nanny? What happened to you? Were you in a wreck?'

'Let's push Nanny in,' Bobby said lazily. 'And see if she can swim. Can a Nanny swim?'

Jean said no, because she was too heavy. She would sink to the bottom and they would never see her again.

'Then we won't push her in,' Bobby agreed.

For a time there was silence. Overhead a few birds fluttered past, plump specks streaking swiftly across the sky. A small boy on a bicycle came riding hesitantly along the gravel path, his front wheel wobbling.

'I wish I had a bicycle,' Bobby murmured.

The boy careened on past. Across the lake the fat man stood up and knocked his pipe against the bench. He closed his book and sauntered off along the path, wiping his perspiring forehead with a vast red handkerchief.

'What happens to Nannies when they get old?' Bobby asked wonderingly. 'What do they do? Where do they go?'

'They go to heaven.' Jean lovingly thumped the green dented hull with her hand. 'Just like everybody else.'

'Are Nannies born? Were there always Nannies?' Bobby had begun to conjecture on ultimate cosmic mysteries. 'Maybe there was a time before there were Nannies. I wonder what the world was like in the days before Nannies lived.'

'Of course there were always Nannies,' Jean said impatiently. 'If there weren't, where did they come from?'

Bobby couldn't answer that. He meditated for a time, but presently he became sleepy ... he was really too young to solve such problems. His eyelids became heavy and he yawned. Both he and Jean lay on the warm gra.s.s by the edge of the lake, watching the sky and the clouds, listening to the wind moving through the grove of cedar trees. Beside them the battered green Nanny rested and recuperated her meager strength.

A little girl came slowly across the field of gra.s.s, a pretty child in a blue dress with a bright ribbon in her long dark hair. She was coming toward the lake.

'Look,' Jean said. 'There's Phyllis Casworthy. She has an orange orange Nanny.' Nanny.'

They watched, interested. 'Who ever heard of an orange Nanny?' Bobby said, disgusted. The girl and her Nanny crossed the path a short distance down, and reached the edge of the lake. She and her orange Nanny halted, gazing around at the water and the white sails of toy boats, the mechanical fish.

'Her Nanny is bigger than ours,' Jean observed.

'That's true,' Bobby admitted. He thumped the green side loyally. 'But ours is nicer. Isn't she?'

Their Nanny did not move. Surprised, he turned to look. The green Nanny stood rigid, taut. Its better eye stalk was far out, staring at the orange Nanny fixedly, unwinkingly.

'What's the matter?' Bobby asked uncomfortably.

'Nanny, what's the matter?' Jean echoed.

The green Nanny whirred, as its gears meshed. Its treads dropped and locked into place with a sharp metallic snap. Slowly its doors retracted and its grapples slithered out.

'Nanny, what are you doing?' Jean scrambled nervously to her feet. Bobby leaped up, too.

'Nanny! What's going on?'

'Let's go,' Jean said, frightened. 'Let's go home.'

'Come on, Nanny,' Bobby ordered. 'We're going home, now.'

The green Nanny moved away from them; it was totally unaware of their existence. Down the lake-side the other Nanny, the great orange Nanny, detached itself from the little girl and began to flow.

'Nanny, you come back!' the little girl's voice came, shrill and apprehensive.

Jean and Bobby rushed up the sloping lawn, away from the lake. 'She'll come!' Bobby said. 'Nanny! Please come!'

But the Nanny did not come.

The orange Nanny neared. It was huge, much more immense than the blue Mecho jaw-model that had come into the back yard that night. That one now lay scattered in pieces on the far side of the fence, hull ripped open, its parts strewn everywhere.

This Nanny was the largest the green Nanny had ever seen. The green Nanny moved awkwardly to meet it, raising its grapples and preparing its internal shields. But the orange Nanny was unbending a square arm of metal, mounted on a long cable. The metal arm whipped out, rising high in the air. It began to whirl in a circle, gathering ominous velocity, faster and faster.

The green Nanny hesitated. It retreated, moving uncertainly away from the swinging mace of metal. And as it rested warily, unhappily, trying to make up its mind, the other leaped.

'Nanny!' Jean screamed.

'Nanny! Nanny!'

The two metal bodies rolled furiously in the gra.s.s, fighting and struggling desperately. Again and again the metal mace came, bashing wildly into the green side. The warm sun shone benignly down on them. The surface of the lake eddied gently in the wind.

'Nanny!' Bobby screamed, helplessly jumping up and down.

But there was no response from the frenzied, twisting ma.s.s of crashing orange and green.

'What are you going to do?' Mary Fields asked, tight-lipped and pale.

'You stay here.' Tom grabbed up his coat and threw it on; he yanked his hat down from the closet shelf and strode toward the front door.

'Where are you going?'

'Is the cruiser out front?' Tom pulled open the front door and made his way out onto the porch. The two children, miserable and trembling, watched him fearfully.

'Yes,' Mary murmured, 'it's out front. But where-'

Tom turned abruptly to the children. 'You're sure she's - dead dead?'

Bobby nodded. His face was streaked with grimy tears. 'Pieces ... all over the lawn.'

Tom nodded grimly. 'I'll be right back. And don't worry at all. You three stay here.'

He strode down the front steps, down the walk, to the parked cruiser. A moment later they heard him drive furiously away.

He had to go to several agencies before he found what he wanted. Service Industries had nothing he could use; he was through with them. It was at Allied Domestic that he saw exactly what he was looking for, displayed in their luxurious, well-lighted window. They were just closing, but the clerk let him inside when he saw the expression on his face.

'I'll take it,' Tom said, reaching into his coat for his checkbook.

'Which one, sir?' the clerk faltered.

'The big one. The big black one in the window. With the four arms and the ram in front.'

The clerk beamed, his face aglow with pleasure. 'Yes sir!' he cried, whipping out his order pad. 'The Imperator Deluxe, with power-beam focus. Did you want the optional high-velocity grapple-lock and the remote-control feedback? At moderate cost, we can equip her with a visual report screen; you can follow the situation from the comfort of your own living room.'

'The situation?' Tom said thickly.

'As she goes into action.' The clerk began writing rapidly. 'And I mean action action - this model warms up and closes in on its adversary within fifteen seconds of the time it's activated. You can't find faster reaction in any single-unit models, ours or anybody else's. Six months ago, they said fifteen seconds closing was a pipe dream.' The clerk laughed excitedly. 'But science goes on.' - this model warms up and closes in on its adversary within fifteen seconds of the time it's activated. You can't find faster reaction in any single-unit models, ours or anybody else's. Six months ago, they said fifteen seconds closing was a pipe dream.' The clerk laughed excitedly. 'But science goes on.'

A strange cold numbness settled over Tom Fields. 'Listen,' he said hoa.r.s.ely. Grabbing the clerk by the lapel he yanked him closer. The order pad fluttered away; the clerk gulped with surprise and fright. 'Listen to me,' Tom grated, 'you're building these things bigger all the time - aren't you aren't you? Every year, new models, new weapons. You and all the other companies - building them with improved equipment to destroy each other.'

'Oh,' the clerk squeaked indignantly. 'Allied Domestic's models are never never destroyed. Banged up a little now and then, perhaps, but you show me one of our models that's been put out of commission.' With dignity, he retrieved his order pad and smoothed down his coat. 'No, sir,' he said emphatically, 'our models survive. Why, I saw a seven-year-old Allied running around, an old Model 3-S. Dented a bit, perhaps, but plenty of fire left. I'd like to see one of those cheap Protecto-Corp. models try to tangle with destroyed. Banged up a little now and then, perhaps, but you show me one of our models that's been put out of commission.' With dignity, he retrieved his order pad and smoothed down his coat. 'No, sir,' he said emphatically, 'our models survive. Why, I saw a seven-year-old Allied running around, an old Model 3-S. Dented a bit, perhaps, but plenty of fire left. I'd like to see one of those cheap Protecto-Corp. models try to tangle with that that.'

Controlling himself with an effort, Tom asked: 'But why? What's it all for? What's the purpose in this - compet.i.tion between them?'

The clerk hesitated. Uncertainly, he began again with his order pad. 'Yes, sir,' he said. 'Compet.i.tion; you put your finger right on it. Successful compet.i.tion, to be exact. Allied Domestic doesn't meet compet.i.tion - it demolishes demolishes it.' it.'

It took a second for Tom Fields to react. Then understanding came. 'I see,' he said. 'In other words, every year these things are obsolete. No good, not large enough. Not powerful enough. And if they're not replaced, if I don't get a new one, a more advanced model-'

'Your present Nanny was, ah, the loser?' The clerk smiled knowingly. 'Your present model was, perhaps, slightly anachronistic? It failed to meet present-day standards of compet.i.tion? It, ah, failed to come out at the end of the day?'

'It never came home,' Tom said thickly.

'Yes, it was demolished ... I fully understand. Very common. You see, sir, you don't have a choice. It's n.o.body's fault, sir. Don't blame us; don't blame Allied Domestic.'

'But,' Tom said harshly, 'when one is destroyed, that means you sell another one. That means a sale for you. Money in the cash register.'

'True. But we all have to meet contemporary standards of excellence. We can't let ourselves fall behind ... As you saw, sir, if you don't mind my saying so, you saw the unfortunate consequences of falling behind.'

'Yes,' Tom agreed, in an almost inaudible voice. 'They told me not to have her repaired. They said I should replace her.'

The clerk's confident, smugly beaming face seemed to expand. Like a miniature sun, it glowed happily, exaltedly. 'But now you're all set up, sir. With this model you're right up there in the front. Your worries are over, Mr ...' He halted expectantly. 'Your name, sir? To whom shall I make out this purchase order?'

Bobby and Jean watched with fascination as the delivery men lugged the enormous crate into the living room. Grunting and sweating, they set it down and straightened gratefully up.

'All right,' Tom said crisply. 'Thanks.'

'Not at all, mister.' The delivery men stalked out, noisily closing the door after them.

'Daddy, what is it?' Jean whispered. The two children came cautiously around the crate, wide-eyed and awed.

'You'll see in a minute.'

'Tom, it's past their bedtime,' Mary protested. 'Can't they look at it tomorrow?'

'I want them to look at it now now.' Tom disappeared downstairs into the bas.e.m.e.nt and returned with a screwdriver. Kneeling on the floor beside the crate he began rapidly uns.c.r.e.w.i.n.g the bolts that held it together. 'They can go to bed a little late, for once.'

He removed the boards, one by one, working expertly and calmly. At last the final board was gone, propped up against the wall with the others. He unclipped the book of instructions and the 90-day warranty and handed them to Mary. 'Hold onto these.'

'It's a Nanny!' Bobby cried.

'It's a huge, huge Nanny!'

In the crate the great black shape lay quietly, like an enormous metal tortoise, encased in a coating of grease. Carefully checked, oiled, and fully guaranteed. Tom nodded. 'That's right. It's a Nanny, a new Nanny. To take the place of the old one.'

'For us us?'

'Yes.' Tom sat down in a nearby chair and it a cigarette. 'Tomorrow morning we'll turn her on and warm her up. See how she runs.'

The children's eyes were like saucers. Neither of them could breathe or speak.

'But this time,' Mary said, 'you must stay away from the park. Don't take her near the park. You hear?'

'No,' Tom contradicted. 'They can go in the park.'

Mary glanced uncertainly at him. 'But that orange thing might-'

Tom smiled grimly. 'It's fine with me if they go into the park.' He leaned toward Bobby and Jean. 'You kids go into the park anytime you want. And don't be afraid of anything. Of anything or anyone. Remember that.'

He kicked the end of the ma.s.sive crate with his toe.

'There isn't anything in the world you have to be afraid of. Not anymore.'

Bobby and Jean nodded, still gazing fixedly into the crate.