me?" Wayne said. "With that? How do you know it's even a gun? Looks more like a fire extinguisher to me. Aw, you poor little imbecile, I haven't had a chance to explain yet, but—"

Sheilah said, "You make me sick." She pulled the trigger.

The object was not a fire extinguisher, after all. It was quite obviously a weapon of some kind.

Also it seemed obvious that Sheilah had been pointing the wrong end of the weapon toward Wayne.

One more obvious fact that Wayne had time to comprehend was that the weapon was not a recoilless type.

But by then Sheilah had gone limp and the gun had rebounded from her grasp and was sailing at Wayne's head.

He ducked but not fast enough. The object whacked him solidly on top of his head.

His brain exploded into a display of dazzling lights, excruciating pain and deafening noise.

Then the lights went out and a long, dense silence set in.

When Wayne fought through the layers of renewed pain and opened his eyes, he was still floating near his makeshift radio equipment in the laboratory.

Sheilah still hung limply in mid-air near the door. The tubular weapon wavered near the ceiling. The radio transmitter was still open.

It was just as though he'd been unconscious no more than a few minutes. But Wayne had a strong feeling that it had been more than that.

Therefore he was only shocked, rather than stunned, when a glance at his wristwatch indicated six hours and forty minutes had elapsed.

He held his head tightly in both hands to keep it from flying off in all directions at once, and he tried to think.

He knew it was important to think—fast and straight.

Six hours and forty minutes.

That was too long to be unconscious from a simple blow on the head, and his head didn't really hurt that bad.

Probably the weapon had still been firing whatever mysterious ammunition it used when it struck him; and when it bounced off his head it had turned, and he'd been caught in its blast.

But that didn't matter. That wasn't the important thing.

Six hours and forty minutes he'd been out.

Seven hours!

The Defense Department official he'd spoken to had told him seven hours.

And thank God it wasn't five hours or six, as he'd been urging them to make it.

Anyway he had only twenty minutes now. Possibly a little more, but just as likely less.

That realization should have spurred him to instantaneous and heroic action, but instead it paralyzed him for several minutes. He couldn't think what to do. He couldn't get his muscles and nerves functioning and coordinated.

The absence of gravity didn't help. He thrashed about futilely.

But at last, almost by accident, his feet touched a metal support beam, and he pushed himself toward Sheilah. He grabbed her around the waist with one arm and with his free hand pulled both of them through the door.

It seemed a long, long time before he got Sheilah to the reconnaissance ship. By then the twenty minutes were up. His life was going into overtime.

Sheilah was conscious but still disorganized and limp, struggling weakly and ineffectually. Wayne fumbled with the door, got it open and shoved her inside.

Then he pulled himself in and closed the door.

They might make it yet. They still had a chance.

He studied the control board, deciding on the proper button to push.

From behind him Sheilah screamed, "The bomb! You've got the bomb and you're going to—Well, you're not!"

Her body slammed against his shoulders and her arms encircled his neck. Her fingers clawed at his eyes.

Wayne struggled, not to free himself, but only to get one hand loose, to reach the control board. When he did get a hand free, they had floated too far from the controls.

"Stop it, you stupid bitch!" Wayne snarled. "You're going to kill us both!"

Wayne said, "Listen, there's a guided missile from earth heading straight for this ship, and it has a hydrogen bomb warhead. It'll