It's early September in Copenhagen, the rain has been coming down for weeks, and 36-year-old journalist Heloise Kaldan is in the middle of a nightmare. One of her sources has been caught lying, and she could lose her job over it. And then she receives the first in a series of cryptic and ominous letters from an alleged killer.

Wanted in connection with the fatal stabbing of a young lawyer three years earlier, Anna Kiel hasn't been seen by anyone since she left the crime scene covered in blood. The police think she's fled the country and have zero clues as to her motive. But homicide detective Erik Sch fer comes up with the first lead when the reporter who first wrote about the case is found murdered in his apartment. Has Anna Kiel struck again, or is there more than one killer at large? And why does every clue point directly to Heloise Kaldan?

Meanwhile, the letters keep coming, and they hint at a connection between Anna and Heloise. As Heloise starts digging deeper, she realizes that, to tell Anna's story, she will have to revisit the darkest parts of her own past--confronting someone she swore she'd never see again.