Five years ago, Ida bravely took the stand against her celebrity therapist Clarissa Virta-and Virta's monstrous husband. Now in her twenties and working alongside her newly sober father at Helsinki Aviisi's crime desk, Ida stumbles upon a disturbing pattern: a series of murders that point to a hidden serial killer stalking the streets of Helsinki. Leading the official investigation is Detective Chief Inspector Kerttu Leppänen, a veteran homicide officer with retirement in sight and ghosts she can't lay to rest. Haunted by unsolved cases and her own regrets, Kerttu is determined to uncover the truth before the killer strikes again. But the past has a way of tightening its grip. And it's not finished with them yet.