connection with Blessing. But, since this was to be the atmosphere of Blessing's house, she was glad that he decided to assign her to take the Mansard papers to the New York laboratory.

Quest came the day before she was scheduled to leave.

Trella was in the living room with Blessing, discussing the instructions she was to give to the laboratory officials in New York. The two bodyguards were with them. The other guards were at their posts.

Trella heard the doorbell ring. The heavy oaken front door was kept locked now, and the guards in the anteroom examined callers through a tiny window.

Suddenly alarm bells rang all over the house. There was a terrific crash outside the room as the front door splintered. There were shouts and the sound of a shot.

“The steel doors!” cried Blessing, turning white. “Let's get out of here.”

He and his bodyguards ran through the back of the house out of the garage.

Blessing, ahead of the rest, leaped into one of the cars and started the engine.

The door from the house shattered and Quest burst through. The two guards turned and fired together.

He could be hurt by bullets. He was staggered momentarily.

Then, in a blur of motion, he sprang forward and swept the guards aside with one hand with such force that they skidded across the floor and lay in an unconscious heap against the rear of the garage. Trella had opened the door of the car, but it was wrenched from her hand as Blessing stepped on the accelerator and it leaped into the driveway with spinning wheels.

Quest was after it, like a chunky deer, running faster than Trella had ever seen a man run before.

Blessing slowed for the turn at the end of the driveway and glanced back over his shoulder. Seeing Quest almost upon him, he slammed down the accelerator and twisted the wheel hard.

The car whipped into the street, careened, and rolled over and over, bringing up against a tree on the other side in a twisted tangle of wreckage.

With a horrified gasp, Trella ran down the driveway toward the smoking heap of metal. Quest was already beside it, probing it. As she reached his side, he lifted the torn body of Dom Blessing. Blessing was dead.

“I'm lucky,” said Quest soberly. “I would have murdered him.”

“But why, Quest? I knew he was afraid of you, but he didn't tell me why.”

“It was conditioned into me,” answered Quest “I didn't know it until just now, when it ended, but my father conditioned me psychologically from my birth to the task of hunting down Dom Blessing and killing him. It was an unconscious drive in me that wouldn't release me until the task was finished.

“You see, Blessing was my father's assistant on Ganymede. Right after my father completed development of the surgiscope, he and my mother blasted off for Io. Blessing wanted the valuable rights to the surgiscope, and he sabotaged the ship's drive so it would fall into Jupiter.

“But my father was able to control it in the heavy atmosphere of Jupiter, and landed it successfully. I was born there, and he conditioned me to come to Earth and track down Blessing. I know now that it was part of the conditioning that I was unable to fight any other man until my task was finished: it might have gotten me in trouble and diverted me from that purpose.”

More gently than Trella would have believed possible for his Jupiter-strong muscles, Quest took her in his arms.

“Now I can say I love you,” he said. “That was part of the conditioning too: I couldn't love any woman until my job was done.”

Trella disengaged herself.

“I'm sorry,” she said. “Don't you know this, too, now: that you're not a man, but an android?”

He looked at her in astonishment, stunned by her words.

“What in space makes you think that?” he demanded.

“Why, Quest, it's obvious,” she cried, tears in her eyes. “Everything about you … your