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 outclassed 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 glass 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 passed 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.