n was summoned.

The pattern of Dr. Simon Cartwright's encephalic emanations, and the
approximate position of the center of these emanations were impressed
on its mind. And in a strangely bulbous ship it plunged outward from
that eternally dark and silent planet towards Earth.

* * * * *

A man was walking along a road. A high road. A silent, dark road.
Below him on both sides of the road flat marshland swept away, and a
little wind caressed him with chill fingers. His tiny world of road
beneath him, darkness around him, sky above him, contained only the
sound of his footsteps--and one other. A regular, liquid sound. He
thought it was a sound from the marsh. He listened to it, and wondered
how long it had been with him. It was close behind him on the road. He
stopped, turned round in small curiosity, and bellowed in great
horror. He threw up his hands against an immense bulk, a frog-like
shape, a lurching, flowing movement. Then it was upon him, and stilled
his futile writhings, and passed over him, and left him dead.

The Assassin continued along the road. It was aware that it had
killed, but it could not contemplate the fact. It possessed all the
mental powers of its race, but its conditioning had focused them in
one direction, the assassination of Dr. Cartwright. It could consider
only those factors which had a direct relation to that purpose.

Daylight was one of those factors.

It was not aware of the passage of time, but when the sensitive patch
on its back began to contract it left the road and went to the marsh.
There it burrowed into the slime until green-flecked water closed over
it. And deeper until a depth of mud protected it from the sun.

Dr. Cartwright groaned and sat up in bed. He silenced the ringing
telephone by putting the receiver to his ear.

"Do you know what time it is?" he asked, aggrieved.

"Hello? Doctor Cartwright? This is the police."

"It is half-past seven," continued Simon. "For me, the middle of the
night. I am in no fit state to measure a drunk's reactions."

"I'm sorry, sir, but there's been an accident. On the Waverton
Highway. A man is dead, Inspector Andrews is in charge of the case."

"Inspector Andrews? Is mayhem suspected? Never mind, I'll get down
there, right away."

He put the receiver down and got out of bed. His wife muttered
something unintelligible and wrapped his share of the blankets round
her. Simon went downstairs. He made