Lydia Douglas has long dreamed of starting her own business, and it had to happen that difficulties arose already with her first client—Aleksei Roshchin hires a girl to compile his family tree. He’s interested in the history of the Roshchins’ family, specifically the story of his great-great-grandmother Irina, from whom a pocket Bible remained, a small antique key that—unknown what it opened—and a beautiful love story with Aleksei Roshchin, who later became her husband. But Irina’s happiness didn’t last long: her husband was murdered because of one treacherous woman. And now, from the 21st century, Aleksei Roshchin asks Lydia to sort out old family secrets. A golden key will help her. It was kept in the Roshchin family for several centuries and—according to legend—can open any door and reveal any secret…