Rab Crane struggled wildly in the robot's inflexible grasp.
Then he opened his mouth to shout for help. Better anything than that Kark Al keep the secret.
"No! You do not give an alarm!" Kark Al hissed, and sprang forward with pistol raised butt foremost.
It crashed down on Crane's head in a stunning blow and the TSS man knew nothing more.
When he returned to consciousness he found himself wearing a heavy flexible metal suit. A spacesuit! Its glassite-fronted helmet was on his head and he breathed tangy oxygen from the tank inside the airtight suit.
Crane tried to rise and found that the wrists of his spacesuit were tied together. Beside him lay Lalla Dee, unconscious and similarly clad in a spacesuit, also bound. They were in one of the Vulcan's space-locks, both inner and outer doors closed.
Then Crane saw Kark Al. The Martian was getting into another spacesuit. The great robot stood motionless beside its master.
Kark Al bent over Crane finally, said coolly in his muffled voice, "Thoh got you from my cabin to this space-lock without anyone in the ship seeing us. Now we are leaving the ship!"
The Martian, once inside his suit, quickly secured a chain to his belt and tied it to the waists of the others so that he and the two prisoners and the robot formed a human chain.
Then Kark Al quickly took down from the rack beside the row of spacesuits, a hand-rocket — a small affair whose reactive push was enough to move several people in the void.
Kark Al touched a button and the outer door of the lock slid open. The air in it puffed out with a sharp sound, and they looked out into the star-gemmed blackness of space.
Rab Crane saw now that the Martian had slung from his shoulders a square, insulated case which he knew contained the brain of Doctor Alph. And as he realized that the Martian was achieving final success, he tried desperately to attack him.
But Kark Al at that moment stepped calmly out from the lock into empty space! The chain at his belt yanked Lalla Dee and Rab and the robot after him. They all floated there in space, a human chain, scraping the hull of the huge liner as it forged onward.
Kark Al's hand-rocket flashed flame, its impulse dragging them all forward. They moved outward from the liner, pulling away from its gravitational drag. The stem of the liner dwindled swiftly until only its lights were visible, and then those too vanished. The Vulcan was gone! They floated alone here in space, the Martian and his two bound, helpless prisoners and the great impassive robot, who needed no spacesuit because he did not breathe. Kark Al no longer used his hand-rocket, now that they were free of the liner. Crane knew that he was waiting for the Martian cruiser to reach them.
They turned slowly as they floated there, the immense starry firmament seeming to revolve around them. Rab glimpsed Lalla Dee's white face, conscious now, through the glassite front of her helmet. His own heart was numb with the cold of ultimate failure.
A few lights appeared against the stars in the direction opposite that in which the Vulcan had gone. The lights came closer and Rab saw they were those of a long, grim black spaceship coming slowly and cautiously through the void. The Martian cruiser that had been secretly trailing the Vulcan!
Kark Al flashed his hand-rocket three times, then repeated the signal. The Martian cruiser veered, came toward them, its bow rocket-tubes firing to brake its speed. The human chain was drawn slowly toward the cruiser by its gravitational attraction. Soon they bumped along its metal side.
Kark Al drew them toward a space lock that waited, open and ready. He jerked them inside and shut the outer door. Air hissed into the lock from storage tanks. Then the inner door of the lock opened and into it ran a half-dozen men; red-skinned, bristling-haired Martian officers in the gray uniform of their planet, and pulled them into the ship's inside.
One of them was the captain of the cruiser. Excitedly he helped Kark Al out of his spacesuit. Crane and Lalla Dee, still in their suits, lay beside the silent robot.
"Nald Arkol, did you get the great secret?" the Martian captain cried.
Kark Al's eyes flashed behind his spectacles as he answered, pointing to the square insulated case he had brought.
"Yes, I got it! The brain of Doctor Alph and his secret!"
He drew from his pocket a metal tube and took out of it a glassite vial filled with a yellow, fluffy substance.
He held it up proudly.
"Gentlemen, this is the secret that will make our planet sole master of the Solar System. This culture will destroy all life on every world, and give us all nine planets for our empire!"
The Martian officers cheered wildly, their faces flaming.
"The day of Mars has come at last!" they yelled.
Rab Crane's brain was a turmoil as he looked through his helmet at the vial Kark Al held aloft. The deadly culture — and it was in a glassite vial! The TSS man saw, in that instant, the superhuman chance to snatch eight planets from the jaws of doom!
He took that chance! With one wild upward lunge, Crane threw himself forward. His tied metal-clad hands struck the vial in Kark Al's grasp and knocked it to the floor. The glassite vial tinkled to shattered fragments.
"Gods of Mars!" screamed Kark Al as the vial broke. Then death was on him, was on them all, and those were his last words.
The fluffy yellow substance on the floor seemed to explode outward ever the Martians, expanding with the speed of light, covering them with a thick blanket of yellow fluff faster than the eye could follow.
It was the deadly bacteriophage Doctor Alph had cultivated, multiplying with the incredible speed the scientist had spoken of, devouring the flesh of the Martians like flame devouring tinder!
Kark Al and the other Martians were already indistinguishable, disintegrating mounds of yellow fluff. The stuff covered the helmets and space-suits of Rab Crane and Lalla Dee but could not penetrate through their air-tight glassite suits.
Crane brushed the yellow fluff wildly from before the eyes in his helmet, saw that the incredibly expanding bacteriophage had puffed out through the whole interior of the Martian cruiser. He could hear dim screams as every man in the ship, every atom of organic life, was fastened on and devoured by the culture.
Then, in a short while there was silence inside the cruiser. The Martians were gone, devoured. The ship held only the masses of ravening yellow life that had destroyed them!
Crane staggered close to Lalla Dee.
"Try to unbind my wrists," he said in a muffled voice, through the helmet. "But for God's sake don't open your suit in the slightest or you're doomed!"
"I'll — I'll try," said the Venusian girl shakenly.
Her trembling bound hands finally managed to undo the bonds around Crane's wrists. He unbound her, then, and released the chain that had tied them to Kark Al and the robot.
The huge robot, Thoh, still stood immobile beside them. The mechanical man's metal body had not been affected by the devouring bacteriophage, but he had received no order from his master to act, and had not moved.
Crane pushed Lalla Dee into the space-lock and told her:
"Take a hand-rocket and get as far out in space from the ship as you can. I'll be with you in a moment."
She obeyed, opening the outer door of the lock, stepping out into the void and using the hand-rocket she had picked up to propel her away from the Martian cruiser.
In a few minutes she saw Crane's space-suited figure leaping out of the space-lock, using another hand-rocket. She met him, grasped his arm as they floated together at a distance from the cruiser.
"What did you do?" she cried to him, her voice conducted to him by their touching space-suits.
"I made sure that that cruiser will never drift onto any world and loose that awful plague there," he told her. "I laid a fuse to its tanks of rocket fuel."