exploded almost at Calhoun's feet.
There were two men in the first-moving ground car, and now that
another car moved to head them off, one fired desperately and the
other tried to steer and fire at the same time. The siren-sounding car
send a stream of bolts at them. But both cars jounced and bounced.
There could be no marksmanship under such conditions.

[Illustration]

But a bolt did hit. The two-man car dipped suddenly to one side. Its
fore part touched ground. It slued around, and its rear part lifted.
It flung out its two passengers and with an effect of great
deliberation it rolled over end for end and came to a stop upside
down. Of its passengers, one lay still. The other struggled to his
feet and began to run--toward Calhoun. He fired desperately, again and
again----

Bolts from the pursuing car struck all round him. Then one struck him.
He collapsed.

Calhoun's hands clenched. Automatically, he moved toward the other
still figure, to act as a medical man does when somebody is hurt. The
grid operator seized his arm. As Calhoun jerked to get free, that
second man stirred His blaster lifted and rasped. The little pellet of
ball-lightning grazed Calhoun's side, burning away his uniform down to
the skin, just as there was a grating roar of blaster fire. The second
man died.

"Are you crazy?" demanded the grid operator angrily. "He was a para!
He was here to try to kill you!"

The police head snapped:

"Get that car sprayed! See if it had equipment to spread contagion!
Spray everything it went near! And hurry!"

There was silence as men came from the spaceport building. They pushed
a tank on wheels before them. It had a hose and a nozzle attached to
it. They began to use the hose to make a thick, foglike, heavy mist
which clung to the ground and lingered there. The spray had the biting
smell of phenol.

"What's going on here?" demanded Calhoun angrily. "Damnation! What's
going on here?"

The Minister for Health said unhappily:

"Why ... we've a public-health situation we haven't been able to meet.
It appears to be an epidemic of ... of ... we're not sure what, but it
looks like demoniac possession."

II

"I'd like," said Calhoun, "a definition. Just what do you mean by a
para?"

Murgatroyd echoed his tone in an indignant, "_Chee-chee!_"

This was twenty minutes later. Calhoun had gone back into the Med Ship
and treated the blaster burn on his side. He'd changed his clothing
from the scorched