llite, small groups began to charge
toward the loading ships in a frenzy of fear. Since Titan had been
colonized, there had never been a single occasion where the sirens had
warned of the failure of the screens. There had been many tests,
especially for the school-age children and the miners working far below
the surface of the satellite, but this was the first time the sirens
howled a real warning of danger and death.

Strong raced back to the control tower of the spaceport in a jet car and
burst into the room where the captain was still asleep on the couch.
Strong shook him violently.

"Wake up, Joe!" he cried. "Come on. Wake up."

"Uh--ahhh? What's the--?" Howard sat up and blinked his eyes. "Steve,
what's going on?"

"The screen at sector twelve has collapsed. How many people are still in
there?"

"Collapsed! Sector twelve?" Howard, still groggy with sleep, dumbly
repeated what Strong had said.

Strong drew back his hand and slapped him across the face. "Come out of
it, Joe!" he barked.

Howard reeled back and then sat up, fully awake.

"What--what did you say?" he stammered.

"Sector twelve has gone," Strong repeated. "How many people are left
there?"

"We haven't even begun operations there yet," Howard replied grimly.
"How long have I been asleep?"

"A couple of hours."

"Then there's still time."

"What do you mean?"

"Just before I folded, I ordered the evacuation crews to start working
on sector eleven. They should be finished now and just about starting on
twelve. If they have, we have a good chance of saving everyone."

"Let's go."

The two men raced out of the control tower to the jet car and roared
through the desolate streets of the city. All around them commandeered
jet cars raced toward the critical area. Commander Walters stood in the
middle of an intersection on the main road to sector twelve, waving his
arms and shouting orders to the enlisted guardsmen and volunteer miners
that had raced back into the city to help. On the sidewalk, enlisted
guardsmen handed out extra oxygen masks to the men who would search the
area for anyone who might not have gotten out before the screen
exploded. The main evacuation force that had been under Howard's
supervision had already moved in but there was still a large area to
cover.

"We'll split up into six sections!" roared Walters, standing on top of a
jet car. "Go down every street and alley, and make a house-to-house
search. Cover every squ