Living on the streets of Philadelphia, Kacey is gripped by opioid addiction, while her sister Mickey, walks those same blocks on her police beat. They don't speak anymore, but Mickey never stops worrying about her sibling. Then Kacey disappears, suddenly, at the same time that a mysterious string of murders begins, and Mickey becomes dangerously obsessed with finding the culprit—and her sister—before it's too late.

"This is not just a gripping mystery but a thoughtful, powerful novel by a writer who displays enormous compassion for her characters…. I absolutely loved it."—Paula Hawkins