ke a chance on the
other one getting back...." He broke off, his eyes on the viewscreen.
"Did you check those scout ships?"

"No, I thought...."

"Get down there and check them." Doc turned back to the viewscreen
impatiently.

Greg caught Johnny's eye, saw the big miner's worried frown. "Where is
he?" he whispered.

"I don't know. Thought you did...."

"All I know is that he had some kind of scheme in mind."

"Shut up," Doc said to them. "If you're smart, you'll be strapping down
before we...." He broke off in mid sentence, listening.

Quite suddenly, the Ranger ship had begun to vibrate. Somewhere, far
away, there was the muffled rumble of engines.

Doc whirled to the viewscreen. Greg and Johnny looked at the same
instant, and Johnny groaned.

Below them, the _Scavenger_'s jets were flaring. First the pale starter
flame, then a long stream of fire, growing longer as the engines
developed thrust.

Doc slammed down a switch, roared into a speaker. "That scout
ship ... stop it! He's trying to make a break!"

Two guards appeared at the lock almost instantly, but it was too late.
Already she was straining at her magnetic cable moorings; then the
exhaust flared, and the little scout ship leaped away from the
orbit-ship, moving out at a tangent to the asteroid's orbit, picking up
speed, moving faster and faster....

In toward the orbit of Mars.

The man called Doc had gone pale. Now he snapped on the speaker again.
"Frank? Stand by on missile control. He's asking for it."

"Right," the voice came back. "I'm sighting in."

The _Scavenger_ was moving fast now, dwindling in the viewscreen. One
panel of the screen went telescopic to track her. "All right," Doc said.
"Fire one and two."

From both sides of the Ranger, tiny rockets flared. Like twin bullets
the homing shells moved out, side by side, in the track of the escaping
_Scavenger_. With a strangled cry, Greg leaped forward, but Johnny
caught his arm.

"Johnny, _Tom's on ... that thing_...."

"I know. But he's got a chance."

Already the homing shells were out of sight; only the twin flares were
visible. Greg stared helplessly at the tiny light-spot of the
_Scavenger_. At first she had been moving straight, but now she was
dodging and twisting, her side-jets flaring at irregular intervals. The
twin pursuit shells mimicked each change in course, drawing closer to
her every second.

And then there was a flash, so brilliant it nearly blinded them, a