When farmers cutting turf in an Irish peat bog make a grisly discovery--the perfectly preserved head of a young woman with long red hair--Irish archaeologist Cormac Maguire and American pathologist Nora Gavin must use cutting-edge techniques to preserve ancient evidence. Because the bog's watery, acidic environment prevents decay, it's difficult to tell how long the red-haired girl has been buried--two years, two centuries, or even much longer.

Who is she? The extraordinary find leads to even more disturbing puzzles. The red-haired girl is not the only enigma in this remote corner of Galway. Two years earlier, Mina Osborne, the wife of a local landowner, went for a walk with her young son and vanished without a trace. Could they, too, be hidden in the bog's treacherous depths, only to be discovered centuries from now? Or did Hugh Osborne murder his family, as some villagers suspect? Bracklyn House, Osborne's stately home, holds many secrets, and Nora and Cormac's inquiries threaten to expose them all.