Shann studied him and knew that Thorvald was telling the truth. He could remember nothing of his departure in the outrigger, the way he had fought Shann in the lagoon. The Survey officer must have been under the control of the Warlockians then. Quickly he gave the older man his version of the other's actions in the outer world and Thorvald was clearly astounded, though he did not question the facts Shann presented. "They just _took_ me!" Thorvald said in a husky half whisper. "But why? And why are we here? Is this a prison?" Shann shook his head. "I think all this"--a wave of his hand encompassed the green wall, what lay beyond it, and in it--"is a test of some kind. This dream business.... A little while ago I got to thinking that I wasn't here at all, that I might be dreaming it all. Then I met you." Thorvald understood. "Yes, but this _could_ be a dream meeting. How can we tell?" He hesitated, almost diffidently, before he asked: "Have you met anyone else here?" "Yes." Shann had no desire to go into that. "People out of your past life?" "Yes." Again he did not elaborate. "So did I." Thorvald's expression was bleak; his encounters in the fog must have proved no more pleasant than Shann's. "That suggests that we do trigger the hallucinations ourselves. But maybe we can really lick it now." "How?" "Well, if these phantoms are born of our memories there are about only two or three we could see together--maybe a Throg on the rampage, or that hound we left back in the mountains. And if we do sight anything like that, we'll know what it is. On the other hand, if we stick together and one of us sees something that the other can't ... well, that fact alone will explode the ghost." There was sense in what he said. Shann aided the officer to his feet. "I must be a better subject for their experiments than you," the older man remarked ruefully. "They took me over completely at the first." "You were carrying that disk," Shann pointed out. "Maybe that acted as a focusing lens for whatever power they use to make us play trained animals." "Could be!" Thorvald brought out the cloth-wrapped bone coin. "I still have it." But he made no move to pull off the bit of rag about it. "Now"--he gazed at the wall of green--"which way?" Shann shrugged. Long ago he had lost any idea of keeping a straight course through the murk. He might have turned around any number of times since he first walked blindly into this place. Then he pointed to the packet Thorvald held. "Why not flip that?" he asked. "Heads, we go that way--" he indicated the direction in which they were facing--"tails, we do a rightabout-face." There was an answering grin on Thorvald's lips. "As good a guide as any we're likely to find here. We'll do it." He pulled away the twist of cloth and with a swift snap, reminiscent of that used by the Warlockian witch to empty the bowl of sticks, he tossed the disk into the air.