As in Hart’s Haunted Ground
and Lake of Sorrows
, the bittersweet Celtic otherworld haunts her outstanding third tale of family sorrows centered on the ancient mystery of what keeps a woman in a bad relationship. After three years of studying Irish “bog people,” corpses preserved in peat fields, Nora Gavin realizes she has to leave Ireland for Saint Paul, Minn., her childhood home, to prove that her architect brother-in-law, Peter Hallett, who’s about to remarry, murdered her sister, Tríona, five years earlier. A desire to protect Tríona’s 11-year-old daughter, Elizabeth, from Peter’s savagery also motivates her. Woven deftly into Nora’s real-world mission are the old Irish selkie stories, tales of seals who shape-change into women, marry for love, and find themselves tragically caught between two worlds, a duality Hart suggests is deeply embedded in humanity. Many readers will find this passionate, complex novel almost impossible to put down. (Mar.)