When Thad started down the companionway to the officers' quarters, in the central one of the five main compartments of the ship, the dog kept close to his legs, growling, trembling, hackles lifted. Sensing the animal's terror, pitying it for the naked fear in its eyes, Thad wondered what dramas of horror it might have seen. The cabins of the navigator, calculator, chief technician, and first officer were empty, and forbidding with the ominous silence of the ship. They were neatly in order, and the berths had been made since they were used. But there was a large bloodstain, black and circular, on the floor of the calculator's room. The captain's cabin held evidence of a violent struggle. The door had been broken in. Its fragments, with pieces of broken furniture, books, covers from the berth, and three service pistols, were scattered about in indescribable confusion, all stained with blood. Among the frightful debris, Thad found several scraps of clothing, of dissimilar fabrics. The guns were empty. * * * * * Attempting to reconstruct the action of the tragedy from those grim clues, he imagined that the five officers, aware of some peril, had gathered here, fought, and died. The dog refused to enter the room. It stood at the door, looking anxiously after him, trembling and whimpering pitifully. Several times it sniffed the air and drew back, snarling. Thad thought that the unpleasant earthy odor he had noticed upon opening the face-plate of his helmet was stronger here. After a few minutes of searching through the wildly disordered room, he found the ship's log--or its remains. Many pages had been torn from the book, and the remainder, soaked with blood, formed a stiff black mass. Only one legible entry did he find, that on a page torn from the book, which somehow had escaped destruction. Dated five months before, it gave the position of the vessel and her bearings--she was then just outside Jupiter's orbit, Earthward bound--and concluded with a remark of sinister implications: "Another man gone this morning. Simms, assistant technician. A fine workman. O'Deen swears he heard something moving on the deck. Cook thinks some of the doctor's stuffed monstrosities have come to life. Ridiculous, of course. But what is one to think?" Pondering the significance of those few lines, Thad climbed back to the deck. Was the ship haunted by some weird death, that had seized the crew man by man, mysteriously? That was the obvious implication. And if the flier had been still outside Jupiter's orbit when those words were written, it must have been weeks before the end. A lurking, invisible death! The scream he had heard.... * * * * *