“Something ahead!” Thorvald did not slacken the pace set by the brilliant spot of green they trailed. Both of the Terrans feared to fall behind, to lose touch with that guide. Their belief that somehow the traveling disk would bring them to the end of the mist and its attendant illusions had grown firmer with every foot of ground they traversed.
A dark, fixed point, now partly veiled by mist, lay beyond, and it was toward that looming half-shadow that the spinning disk hurtled. Now the mist curled away to display its bulk—larger, blacker and four or five times Thorvald’s height. Both men stopped short, for the disk no longer played pathfinder. It still whirled on its axis in the air, faster and faster, until it appeared to be throwing off sparks, but the sparks faded against a monolith of
