Danish journalist Heloise Kaldan receives the first in a series of cryptic and unsettling letters from a woman named Anna Kiel. Wanted in connection with the fatal stabbing of a young lawyer three years earlier, Anna hasn't been seen by anyone since she left the crime scene covered in blood. While the letters keep coming, 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.