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Den amulett du beskriver är faktiskt från Chronicles of Prydain, fast det är i bok 2, The Black Cauldron, snarare än Castle Llyr eller Taran Wanderer. Den plats där överhänget kollapser är:Taran, who had been thoughtfully fingering the clasp, stopped and looked about him uneasily. “Hurry,” he said, “we must leave here at once.” “Taran of Caer Dallben,” Eilonwy cried, “you’re going too far! I can understand coming out of the rain, but I don’t see deliberately going into it.” Nevertheless, she followed; and the companions, at Taran’s urgent command, untethered the horses and ran from the hillside. They had not gone ten paces before the entire slope, weakened by the downpour, collapsed with a loud roar.
Amuletten gavs till Taran av Adaon, även om den beskrivs som en lås snarare än en amulett.
Adaon shook his head. He put his hand to his throat and undid the iron clasp at the collar of his jacket. “Take this,” he said. “Guard it well. It is a small thing, but more valuable than you know.”