"But I discovered that those destroyed worlds still exist, and I know too well what mad tinkering the others will be prompted to, when they make the same discovery. You must prevent them, as I intended to. In particular, you must find the Probability Engine and summon its true owners, whatever creatures they may be, who built it and who lost the first talisman. They're the only ones fitted to deal with the tangle of problems we have created. But to find the Probability Engine, you must have a talisman. Ters, who destroyed me, took mine, but that was one which I had stolen. My own original talisman is in the possession of Thorn, the Thorn of this world, who stole it from me, I now believe, because of some unconscious prompting from the True Owners, groping through many-layered reality in an effort to find their lost engine. That Thorn is worlds away from here, more worlds than you suspect. But you"--his fingers fumbled sideways, touching those of the other Thorn, who did not withdraw his hand--"can get into touch ... with him ... through your linked ... subconscious minds." The whisper was barely audible. It was obvious that even the talisman-vitalized strength was drawing to an end. "That talisman ... which he has ... is inert. It takes a key-thought ... to unlock its powers. You must transmit ... the key-thought ... to him. The key-thought ... is ... 'Three botched ... worlds--'" The whisper trailed off into a dry rattle, then silence. The jaw fell open. The head slumped forward. Clawly caught it, palm to white forehead, and let it gently down on to the desk, where the groping fingers had traced a black, crisscross pattern. Over it, Clawly's eyes, and those of the other Thorn, met. XII. The coup d'etat may appear in a thousand different guises. The prudent ruler suspects even his own shadow. _de Etienne_ The Sky Room of the Opal Cross was so altered it was hard to believe it had been a festivities center only three days ago. The World Map and Space Map still held their dominating positions, but the one was dotted with colored pictorial symbols indicating the location of spaceports and space-yards, defense installations, armament fabrication and conversion centers, regular and emergency power stations, field headquarters, and like military information, while the Space Map, in which a system of perspective realistically conveyed three-dimensional depth, was similarly dotted in the Marsward sector to indicate the real or hypothetic location of spacecraft. This latter map emphasized with chilling clarity the fact that Earth had nothing at all in the way of an interplanetary battle fleet, only a scattering of unarmed or lightly armed exploratory craft that now, by stretching a point, could be counted as scouts. While fanning out from Mars in a great hemisphere, hypothetic but none the less impressive, loomed a vast armada.