In Ireland of A.D. 666, Sister Fidelma is sent by her brother, Colgu of Cashel, the king of Muman, to the remote valley of Gleann Geis, whose inhabitants still adhere to the ancient Druidic ways. Her mission is to negotiate with the chieftain Laisre for permission to build a Christian church and school in his territory. Fidelma's task won't be an easy one, though, as Laisre's clan is known for its hostility to the new religion and fierce adherence to the old.
Approaching the valley, Fidelma and her companion, Brother Eadulf, come upon a particularly grisly scene--the slain bodies of thirty-three young men, placed in a sunwise circle and bearing the marks of the ancient threefold death of pagan times. As an emissary of her brother the king, as well as her position as a dalaigh--an advocate of the Brehon courts--it is Fidelma's responsibility to uncover the truth behind the gruesome murders. Within the forbidden valley, Fidelma embarks upon an inquiry that not only places her in the gravest personal danger but upon which rests the continuing peace of her brother's kingdom.
Sister Fidelma and Brother Eadulf, her Saxon monk sidekick, are on their way to Gleann Geis, a remote pagan community in southwest Ireland, when they run across a horrible massacre: 33 young men have been ritually killed, their bodies laid out in a pattern peculiar to the ancient Druid faith. (As her fans know from the five novels in this well-researched series, most recently The Spider's Web, religious and political tensions simmer in seventh-century Ireland, though with its sophisticated legal system and fair treatment of women, it is one of Dark Age Europe's more civilized societies.) At Gleann Geis, the pair stumble on another murder, for which Sister Fidelma is arrested. The meek Eadulf has an easier time mounting a clever defense of his mentor than he does fending off the advances of the local chieftain's precocious 14-year-old niece. Released from confinement, Sister Fidelma is free to make full use of her sharp analytical powers to figure out who is behind the massacre and the seemingly unrelated murder of which she was unjustly accused. She does not disappoint. At the climax, the religieuse explains all, untangling a complex web of intrigue that moves from one surprising revelation to the next. While adept at plotting, Tremayne has an annoying habit of overusing adverbs. A door opens "boisterously," a mouth droops "pessimistically," while characters smile "thinly," "wanly," "warmly," "gravely," "grimly," "apologetically" and "maliciously." In the future one hopes that the author--or his editor--will put as much faith in plain verbs as Sister Fidelma does in her God.