"Come in," the Old Man said. "Please sit down, Doctor Fox."

Fox looked with interest at the chief of Military Intelligence. The Old Man pushed a box of cigarettes towards him.

"Help yourself, Doctor. First of all I must thank you for bringing us the weapon -»

Fox interrupted:

"Christian got that weapon for you. Don't you think it is time to clear him of the suspicion of the murder?"

"That is really a matter for the police, but I believe his story. I think I will be able to help." The Old Man looked through some papers. "I have here a report on this weapon. It is a decapitator; and a new kind of energy is used in it. I have no details, but a group of scientists are working on it. The fingerprints on the weapon show that it has been used by somebody with very small hands."

"The Brains!" exclaimed Fox.

"Probably. As you know, the Brains have disappeared completely - my men are watching the Fair, and they haven't seen them. I don't think they will come to the Fair again."

"We must get one of those crystals," said Fox. "Lawrence worked with rockets. Duval worked out a new theory for the space-time continuum. Do you see what we are up against? These murders aren't going to stop - you can be sure that the Brains have more than one decapitator. It is an interplanetary affair. The earth is fighting for the right to go out into space…"

The Old Man looked grim.

"If you are right," he said, "the position is serious. What have we got? An invasion by beings from another world who can disappear at will and who have a deadly weapon - deadlier than ours. We must find them. If only we knew where to start looking -»

"They have a spaceship which is hidden somewhere," said Fox. "Find the ship and you will find the Brains. I advise you to check all unidentified flying objects which appear in the sky."

"I'll do that. Now, if you'll excuse me, I must see the Prime Minister immediately."

Fox said quickly: "And Christian? Will you clear him?"

"Yes. I'll speak with the Home Secretary. Later, I should like to meet the captain personally."

Fox walked along the corridor and left the building of Military Intelligence. He heard the voice of a newsboy:

"Another decapitation! The maniac strikes again! Special!"

Fox bought a newspaper. It told of an Italian scientist who had been found dead in his laboratory. Fox had a feeling that the real trouble was only just starting. First Britain, now Italy…

Where next? He wondered.

From the window of his office on the sixty-fourth floor Michael Brant had a very good view of downtown Manhattan. But he was not looking through the window. He was sitting with his back to the window. He was a fat man with rings on his fingers and a big cigar between his teeth.

"It is interesting," he said slowly. "Of course, it is interesting, but where is money in it? You agree that it will take a lot of money to make something practical out of this model of yours, don't you?"

He was looking at the inventor who was standing in front of him.

"I haven't the money to do it myself," said the inventor. "That's why I came to you. I need a research laboratory. But I am sure that you will get your money back in the end."

"In the end!" Brant smiled cynically. "Listen, Marten, I am a financier, not a philanthropist. I want results - now. All right," he went on, "I'll give you five thousand."

"Ten," said Marten.

At this moment, though the door was locked, a dwarf-like figure, dressed in grey, suddenly appeared in the room. The man raised his hand and pointed a strange-looking gun at Marten. A bright ray appeared from the gun

The next moment Marten's headless corpse fell on the floor. The weapon turned to Brant…

Afterwards the man in grey turned the ray on Marten's invention, and then disappeared.

In South America five men died.

In Africa and Mexico, in Sweden and Madagascar, the decapitations continued. Reports from behind the Iron Curtain said that this process was now world-wide. Brains were seen in Berlin, Hawaii, and other places. More and more people were murdered, and all of them were scientists - until the incident in Caribou City.

Caribou City was a small town on the banks of the Peace River in Canada. Uranium had been discovered there, and a group of scientists were doing some research work. One night a scientist was decapitated there in the presence of a large group of people, but this time the Brain who had decapitated him did not escape.

The scientist's assistant had a gun and shot the Brain through his heart.

There was a full hour of triumph in Caribou City. Then the revenge came. There appeared a lot of Brains in the town. They used the weapons which were of the same type as the decapitators, but much bigger and more powerful. Whole buildings were burned to the ground. In a short while Caribou City was completely destroyed…

After that the Brains returned to their practice of killing the world's scientists. Every day reports of new decapitations came from different parts of the world: from Athens and Tokyo, Lisbon and Vienna. Newspapers attacked the governments for doing nothing.

The British Prime Minister declared a state of emergency.

The police and Military Intelligence were looking for the Brains' base, but could not find anything. The Brains simply appeared, killed, and disappeared again.

Sitting in an armchair in the cabin of his yacht, Captain Christian raised his glass.

"It's nice to be a free man again. Thanks, Doc."

Doctor Fox, sitting opposite him, opened a fresh bottle of beer.

"You did it yourself, Chris," he said. "You got the decapitator."

"And you took it to Miller's chief. I could not do it without you."

They sat a few minutes in silence.

"The important thing now," said Christian, "is to find the Brains. We must get one of those crystals."

"I don't see, how you can do that," said Fox. "You can't catch people who disappear into thin air."

"We must try. We must catch one of them before he has time to use his decapitator or touch his crystal. If we work fast, we can do it. And then we'll separate. I'll take the prisoner to a hiding-place which will be prepared - and you will take the crystal somewhere else."

Fox laughed: "First catch your Brain."

Christian smiled.

"We'll make a trap," he said. "We can publish an article in the newspapers that some scientist has found out the mystery of the Brains. The newspaper article will mention the place where this scientist works - and it will be our hiding-place! I am sure the Brains will come to that place at once!"

The doctor thought.

"Maybe it will work," he said.

"I am sure it will work," said Christian. "One of them will come and we'll catch him. And I'll make him talk."

"Shall we ask the Old Man to help?"

"No! This is my show. Afterwards, if we do it, we'll tell him the good news. But I want to do it myself."

He took a note-book and began to write a plan.

"We shall need two fast cars and an empty house in some isolated place. Then two separate hiding places."

Christian worked out the details of his plan.

"Where do they come from?" he asked suddenly. "I don't agree with your theory that they come from interplanetary space. A spaceship large enough to carry fifty Brains cannot be hidden. The astronomers have searched the sky with their telescopes and found nothing. There must be some other explanation. But what?"