But finding the blood he needed—that was only half his problem wasn’t it? There was still the difficulty of the stone itself, the crystal. As the monk had warned, the stone would not last forever. Each application required a bit of it to be dissolved. Iago knew he would eventually use up his Moroccan supply. And so far, apparently, he had been unable to analyze the components of the thing or reproduce the process by which it was made. Ultimately he was going to have to figure out how to create the stone for himself. And he would have to do it before the lines of discoloration began to appear on the backs of his own hands, before he, like William and Anselm and the monk of Belham Abbey, suffered the agonies of living decay.

And that’s where the trail of ghost stories had come in. Twenty years ago. After the destruction of the compound in Argentina. After five years in exile. “In a little place off the Edgware Road,” as he had told her. Somehow, something had led Iago to “Black Annie.” Something had led him to connect that story with “The Alchemist’s Castle,” which linked it to the Rhinehart triptych, and with “Young William,” which linked all the others to the monk’s confession.

And it was the confession, it was surely that, which had begun his twenty-year search for the triptych itself.

Because when he read the monk’s confession, he had noticed—as Harper had noticed—the monk’s claim that he had recorded the formula for the stone in his document. But if that was true, then where had he recorded it? It was not in the words. It appeared nowhere in M. R. James’s translation. Therefore the scribe must have encoded the formula into the illuminations, the pictures. Which were destroyed when the British Library was bombed in 1941.

But which—possibly, even probably—had served as the inspiration for the Rhinehart triptych.

This was the ultimate message of the story trail, of its convoluted chain connecting the Belham monk’s confession to the Rhinehart work. Because if the Rhinehart work was based on the confession, then the triptych was not—as Iago clearly believed it was not—a depiction of the three magi visiting the Madonna and child. No. It showed instead the three conspirators meeting Annie in the woods to perform their sacrifice.

And if Rhinehart had copied the pictures from the Belham manuscript, he might also, knowingly or unknowingly, have copied the coded instructions for the making of the crystal.

He who has eyes to see, let him see.