Suddenly I realized what was wrong. He must have seen that no debris had resulted from the shot! Either he or his instruments thought that he had missed!

He was turning, and even though he was ten miles to our left, I could almost look down his cannon barrel. His instruments had found our turbulence again!

A FLASH!

The tug bucked.

WE WERE HIT!

Suddenly the Will-be Was main drives shrieked into a high whine. , . It was as if a slingshot had been released and we were the pellet!

We vaulted across the black sky in a sickening cartwheel.

Corky's voice: "Damage! Damage! Our traction engines are disabled! We have lost our tow!"

The planet's distant surface was hurtling up at us.

Heller's hand slapped the throttles of the main drives shut. He yanked the planetary auxiliaries wide open.

We were braking at full throttle!

The Earth steadied to the same size for three consecutive seconds and then again began to grow smaller.

Heller was cuffing the controls around.

We faced now toward the vast white bulk of the tow.

An explosion bloomed off to our right.

The assassin ship was firing.

It was now visible to the right of the tow.

With the auxiliaries, Heller jinked toward the explosion spot.

Another explosion flashed to our left.

"Blast him," said Heller. "He's a better gunner!" He was slewing to the left. I knew then that we were up against the lead assassin pilot. Yes, he was the better gunner. He was an expert at killing ships that sought to flee battle. This unarmed, unarmored tug would be nothing for him.

The flying cannon was near the hurtling mass of ice.

Heller made the tug leap far to the right.

A shot exploded just where we had been a split second before.

Heller dived. He hauled up suddenly. And just where we would have gone, fire bloomed!

"He's too good," said Heller. "And he's only firing at turbulence!"

We shifted skyward. The assassin ship was only a mile away. I saw its cannon wink.

Heller's hand closed on his firing pin.

An illusion of the tug appeared to the right of the flying cannon, between it and the ice tow.

The assassin ship turned toward it!

On other screens I could see that we were hurtling down at the top of Earth, the battle travelling at the dizzy speed of advance of that ice mass.

The cannon fired!

The shot went through the illusion and sprayed thousands of tons of ice about.

Heller maneuvered the tug.

The illusion seemed to be closing on the flying cannon.

The assassin pilot fired again. More ice tonnage flew.

The illusion seemed to be broadwise to the other vessel. It seemed to be closing with it sideways!

The flying cannon must have thought that all it had to do was push its muzzle against the tug and shoot.

It charged the illusion!

Heller twitched his controls.

The illusion must be blanking off the entire forward view of the assassin ship! But we were seeing it sidewise.

The flying cannon instruments and viewers must have been all involved with the illusion. He was depending on instruments and otherwise flying blind!

The assassin ship hurtled at its target!

Heller shifted the illusion to keep the assassin ship's nose headed at it and the instruments concentrated on it.

Suddenly I realized that the illusion was penetrating the edge of the ice mass!

The assassin ship made one more charge.

A HUGE GOUT OF ORANGE AND GREEN FIRE!

The flying cannon had plowed straight into the ice mass and exploded!

Ice and flaming chunks of debris made a sphere of their own, close beside the racing mass of frozen water.

Billions and billions of tons of ice were hurtling straight at Earth, out of control.

Oh, Lords," said Heller, "there it goes without its last correction!"

He was looking at the ice mass. Then he looked at the planetary surface. Through the viewports I could make out what must be Canada and Greenland and, over the curve, what must be Sweden, Finland and the north edge of European Russia.

"Quickly, Corky. Damage?"

"Nothing internal," the tug said. "The aft cable ends of the traction beams are totally fused. One mustn't even turn the traction motors back on or they'd explode."

"Time to repair?" said Heller anxiously.

"You don't have the tools aboard."

Heller watched the ice mass. I knew he must be considering some idiotic move like trying to butt it. Butt billions of tons of loose ice? We'd just get buried in it.

He looked at Earth again. "That's going to miss the north pole! Is there no way to give it downward deflection?"

"Bombs. We don't have bombs," said Corky. "My thirty-fourth subbrain says you could butt the planet. But this conflicts with my purpose to protect you from harm. All we would do is explode. The relative mass of our impact and the planet mass are incompatible. Correction. Incomparable. Sir, you are now approaching the mag-netosphere and have your pilot antiradiation plate open. Please dose it."

Heller didn't move. He was looking down at the top of Earth and the hurtling mass of ice. "Oh, Lords," he breathed.

The vast, glistening expanse of ice was closing rapidly. It now had about a hundred thousand miles to go. We were pacing beside it. Our digitals read three hundred miles a second, eighteen thousand miles a minute. Another clock was running backwards: It said there was 5.555 minutes to go. Heller drew a long sigh. He looked over at the ice. He looked at the planet surface. He looked at his instruments.

"Well, it's a good thing we had it slowed down," he said. "There's nothing I can do."

He worked the controls and we drew off.

The great ice mass raced ahead. It was plunging at an angle toward a spot beyond the north pole.

It was going to strike a glancing blow but it would be a blow all the same.

The seconds ticked by into minutes.

I knew the TV would be alive. I wished he would turn it on. This thing would have been spotted within the last hour. There must be bulletins every minute on this "comet" that had suddenly appeared up in the sky. It must be eyeball visible from northern Canada and maybe even England now.

It was closing with ferocious speed, fifteen times that of the average meteorite. It certainly was not on target for the north pole! It was going to miss it and hit at a flatter angle.

Sweden and Finland? No, they were slightly to the right of it.

It was daylight where it was going to hit. And it was going to strike land.

Heller shifted the tug closer and to the left.

The ice mass struck the upper atmosphere. Racing, it began to change its form. At thirty miles a second it had not long to go.

It missed Finland.

It seemed to be spreading out, its mass tumbled by the resistance of air.

Ahead of it I could see now what appeared to be a large inland lake, blue in the brown of Russia. Some of it would hit that lake.

In slow, slow motion as it appeared from on high, it was racing down the last few miles.

IT STRUCK!

It seemed to generate an enormous flash like electricity!

An instant later, the mass seemed to have quadrupled in size! A piece of it had hit the lake!

Like a scythe it was sweeping onward!

Travelling at a low angle, it was levelling everything in its path.

MOSCOW!

One second there was a city.

The next, there was only jumble!

The scythe swept on!

Waves of cloud were racing ahead, southward. They were growing less and less as they progressed toward the Black Sea.

Dust and debris were settling below.

And then I saw what it had done.

The recoil had flattened Leningrad.

Everything that was European Russia had been levelled!

That whole nation was no more!