Inspector Kate Martinelli has worked the SFPD's Homicide Detail for nearly thirty years. She knows all about how a cop builds a case bit by bit to create a clear story from the scattered pieces of evidence. Until the day her fifteen-year-old daughter, Nora, happens to ask about an aunt she'd never met. Kate's kid sister died in the 1980s, a wild young woman who lost control of a car and hit a tree, end of story... except it isn't. Because once Kate begins to look, seeking to reassure Nora that it was only a senseless accident and not the suicide a small town's gossip made it, she starts to find pieces that don't fit the picture. Holes in the evidence. Mismatched fragments that change the story Kate has told herself all these years - the story that for her, was the beginning of everything. What did happen in Diamond Lake that night? Was it an accident, or a hushed-up suicide? Or was her sister's death something darker yet?