Grace Vaccaro's job as a mental health evaluator is to determine whether people are in danger and need to be hospitalized. So when a paranoid man is found murdered on the banks of the Snoqualmie River, she wonders if she could have done more to help him. When her neighbor is found dead in the same location, Grace thinks there's a connection. Her search for answers takes her from the homeless encampments of Seattle to the forests of Snoqualmie Valley, where nothing is clear and danger hides in the shadows.