A little of the light cloud of dust stirred up by the truck wheels had settled over him and clung to the encasing shell. As he moved, these dust specks moved. The effect to the staring guard, Thorn realized, must be that of seeing a queer, fine dust column moving eccentrically over a grassy lawn where no dust column had any business to be. * * * * * Quickly Thorn moved toward the garage, with the eyes of the amazed guard following him. The scientist was savage at the delay; but it was vital that he rid himself of that clinging dust. Behind the garage he broke off a feathery spray from a vine, and stroked it lightly over himself. That, too, presented a curious spectacle: a leafy branch suddenly detaching itself from the parent vine and dancing here and there in mid-air. When the all-important task was done, Thorn raced back to the rear doorway. By great good luck it was still open. He stole in, just making it as the truck driver, staggering under a load of empty crates, came up the cellar stairs and went out to his truck. Thorn drew a deep breath. He was inside the Arvanian Embassy. The place was a three-storied stone trap in which, if the slightest slip revealed him to its tenants, he would surely meet his death. But, anyway, he was inside! And the threatening Ziegler plans waited somewhere near at hand for him to find and take! Even had Thorn not known in advance that trouble was brewing, he could have surmised that something sinister was being hatched in the Arvanian Embassy. For, in this big sunny kitchen five men lounged about in addition to the white-coated chef and his beardless stripling of an assistant. And each of the five had a holster strapped openly over his coat with the butt of an automatic protruding in plain sight. Thorn looked about. Across from the great range, beside which he was standing and holding his breath for fear some one of the seven men should become aware of his presence, was the door leading to the front part of the house. He started toward that door, walking on tiptoe. A shudder crept up his spine as he tiptoed across the floor directly in front of the armed guards who would have shot him down without compunction could they have seen him. He was not yet used to his invisibility; knowing himself to be substantial, feeling his feet descend solidly on the floor, he still could hardly credit the fact that human eyes could not observe him. * * * * * He got to the door. He put out his hand to open it, then realized just in time that he could not do that. A door stealthily opening and closing again, with no apparent hand to manipulate it? Such a spectacle would start a riot!