Dr. Miriam Osei could identify, from a sample of soil on a person's shoes, which part of which city they had walked through in the past forty-eight hours, assuming they had not cleaned the shoes. This was not a trick. It was a skill she had developed over twenty years of forensic pedology and it had resulted in four peer-reviewed papers, two court cases, and a small but dedicated following among criminologists who were not sure how to cite her work in ways that would survive cross-examination. The practical application was narrower than people assumed. She could tell you the type of soil, the likely deposit location, the mineralogical composition, and often the specific district of a city if she had reference samples. She could not tell you why the person had been there. This distinction mattered enormously in courtrooms and mattered very little to the people who contacted her after reading a magazine profile, asking her to find missing family members by their shoes. She had not taken any of those cases. She had thought about them, standing in her lab over samples from other contexts, considering what it meant to know where something had been without knowing why. She had written about this in the acknowledgments section of her third paper, which was not standard practice. The editor had asked her to remove it. She had revised it into a single sentence that she knew only she understood, and it had stayed.