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 grass 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 grass, 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 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."