When she arrives in Scotland, she discovers that her new employer is Peter Quinnell, a legendary archaeologist considered quite mad by the archaeological establishment. Verity, however, is taken by the elderly gentleman's charm. Quinnell confides to Verity that he believes he has discovered the last campsite of the Legio IX Hispana a famous Roman legion that was lost without a trace. Verity is dubious but intrigued. After all, to find evidence of the mysterious fate of the Ninth Legion would be, archaeologically speaking, nearly as fantastic as finding the Holy Grail.
Verity decides to accept the position, because it is a thrilling opportunity, even if risky.
Everything about Scotland seems to thrill her not excluding David Fortune, who, alas, continues to remain icily aloof. Still, Verity settles very happily into her fascinating work. Soon, though, she begins to sense danger lurking in the mists. There appears to be a smuggling operation running from the old house, as they always do in stories of this variety. Such manifestations of the supernatural begin to intrude on Verity's orderly, scientific view of the world, until even she begins to believe in ghosts, and fear that a malevolent force is at work, threatening them all.