d, and there was a
spontaneous burst of laughter. Tommy relaxed and lay back happily.
Anyway, that was the last of Aunt Bee!

* * * * *

The next hour or two passed in a flurry of ringing phones, people coming
and going, and last-minute words and reminders. Then suddenly it was
time to leave. Dad burst in for a last quick hug and a promise to send
him pictures of Douwie and her foal, due next month; Mother dropped a
hasty kiss on his hair and promised to hurry back from the Spaceport.
Then Tommy was alone, with a large, painful lump where his heart ought
to be.

The only activity was the almost noiseless buzzing as the hotel android
ran the cleaner over the living room. Presently even that ceased, and
Tommy lay relaxed and inert, sleepily watching the curtains blow in and
out at the open window. Thirty stories above the street the noises were
pleasantly muffled and remote, and his senses drifted aimlessly to and
fro on the tides of half-sleep.

Drowsily his mind wandered from the hotel's android servants ... to
the strictly utilitarian mechanical monstrosity at home, known
affectionately as "Old John" ... to the android showroom where they
had seen the one that Dad said looked like Mother....

He jolted suddenly, sickeningly awake. Suppose, his mind whispered
treacherously, suppose that Dad _had_ ordered one to take Mom's
place ... not on Mars, but _here_ while she returned to Mars with him.
Suppose that instead of Mom he discovered one of those _Things_ ... or
even worse, suppose he went on from day to day not even knowing....

It was a bad five minutes; he was wet with perspiration when he lay back
on his pillows, a shaky smile tugging at the corners of his mouth. He
had a secret defense against the Terror. He giggled a little at the
thought of what Aunt Bee would say if she knew.

And what had brought him back from the edge of hysteria was the
triumphant knowledge that with the abnormally acute hearing bred in the
thin atmosphere of Mars, no robot ever created could hide from him the
infinitesimal ticking of the electronic relays that gave it life. Secure
at last, his overstrung nerves relaxed and he slid gratefully over the
edge of sleep.

He woke abruptly, groping after some vaguely remembered sound. A soft
clicking of heels down the hall.... Of course, his mother back from the
Spaceport! Now she would be stopping at his door to see if he were
asleep. He lay silently; throug