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 grass, 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 mass of crashing orange and green.

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