On assignment in Vienna, photographer Ian Jarrett falls suddenly and desperately in love with a woman he has met purely by chance, Marian Esguard. Back in England, he separates from his wife and goes to meet Marian at an agreed-upon rendezvous, only to hear her tell him on the telephone that she will not be coming after all. She then vanishes from his life as mysteriously as she entered it. Searching frantically for the woman for whom he has sacrificed everything, Jarrett stumbles upon a Dorset churchyard full of gravestones of dead Esguards. He meets Daphne Sanger, a psychotherapist, who is also looking for someone: a former patient who has come to believe she is the reincarnation of Marian Esguard - a woman who lived in Regency times and, it emerges, may have invented photography ten years before Fox Talbot. But why is Marian Esguard unknown to history? And who and where is the woman Ian Jarrett met and fell in love with in Vienna?