The sensation of being watched faded, as though the watcher had withdrawn to a greater distance. It was perhaps the hundredth time within six days that he had felt the sensation. And when he slept at night something came to nuzzle at his mind; faceless, formless, utterly alien. For the past three nights he had not let the blaster get beyond quick reach of his hand, even when in bed. But whatever it was, it could not be on the ship. He had searched the ship twice, a methodical compartment-by-compartment search that had found nothing. It had to be the work of the natives from outside the ship. Except.... Why, if the natives were telepathic, did the one called Throon go through the weary pretense of trying to learn a mutually understandable form of communication? There was one other explanation, which he could not accept: that he was following in the footsteps of Will Garret of Ship Nine who had deliberately gone into a white sun two months after the death of his twin brother. He looked at the chair beside his own, Johnny's chair, which would forever be empty, and his thoughts went back down the old, bitter paths. The Exploration Board had been wrong when they thought the close bond between identical twins would make them the ideal two-man crews for the lonely, lifetime journeys of the Exploration Ships. Identical twins were too close; when one of them died, the other died in part with him. They had crossed a thousand light-years of space together, he and Johnny, when they came to the bleak planet that he would name Johnny's World. He should never have let Johnny go alone up the slope of the honey-combed mountain--but Johnny had wanted to take the routine record photographs of the black, tiger-like beasts which they had called cave cats and the things had seemed harmless and shy, despite their ferocious appearance. "I'm taking them a sack of food that I think they might like," Johnny had said. "I want to try to get some good close-up shots of them." Ten minutes later he heard the distant snarl of Johnny's blaster. He ran up the mountainside, knowing already that he was too late. He found two of the cave cats lying where Johnny had killed them. Then he found Johnny, at the foot of a high cliff. He was dead, his neck broken by the fall. Scattered all around him from the torn sack was the food he had wanted to give to the cats. He buried Johnny the next day, while a cold wind moaned under a lead-gray sky. He built a monument for him; a little mound of frosty stones that only the wild animals would ever see-- * * * * * A chime rang, high and clear, and the memories were shattered. The orange light above the hyperspace communicator was flashing; the signal that meant the Exploration Board was calling him from Earth. He flipped the switch and said, "Paul Jameson, Exploration Ship One." The familiar voice of Brender spoke: "It's been some time since your preliminary report. Is everything all right?"