There's a real-life Society for Creative Anachronism, which celebrates and researches all things medieval. The author is a member, and her debut novel is set at the annual war-games site, a campground in Pennsylvania. Here, thousands gather to don costumes and weaponry, reproduce the speech, customs and food of the period, pay allegiance to a peerage hierarchy, divide into fiefdoms for their war, and leave their so-called ""mundane"" identities behind. This year when Thorstane, an alcoholic bully a.k.a. Randy Unwin, of the Great Dark Horde, is murdered in the course of battle, the bewildered local cops are ready to arrest Lady Katherine, who found him near death. Her husband Lord Stefan, mundanely a police detective, investigates on his own, interprets correctly the victim's dying words, and finds the real killer. There's a competently worked out puzzle here, buried under a mass of medieval lore. The reader with a compelling interest in the period may stay awake. For others--acute, numbing boredom.