When her estranged ex–reality-star younger sister turns up shoeless and dead of an overdose on a Bronx playground, Lena Scott has to prove to herself-and everyone else-that it was not an accident.Lena may be just 28, but she's as hard-boiled as a millennial gets. A loner, she hasn't had a relationship with her hip-hop–mogul father since she was 4; her mother and grandmother both died five years ago; and she hasn't seen her best friend, who's burying herself in a master's program in nonprofit management at Columbia, in a year. A fan of friends with benefits, she's "never been big on relationships." She doesn't even do social media except to keep tabs on her sister, Desiree, another exile from her life after Desiree's DUI two years ago. Since the police have zero interest in pursuing what Lena knows are suspicious circumstances around Desiree's demise, she hits the streets, uptown and down, by foot and bike, mass transit, and Uber, tracking down leads with baby sister's friends, flings, and-uncomfortably for her-family. If the first 60 pages have a few too many implausibilities (ubiquitous dashing reporters) and bad similes ("her eyes were as dry as my sex life") and the last 60 devolve into eye-glazing digital forensics ("I was about to close Safari when I noticed the GoFundMe site") and a rushed, too-pat end, everything in between crackles. The writing is sharp, the commentary wry, and Lena is irresistible: "I'd never wanted to see a cop more in my twenty-eight years of being Black."Come for the not-so-bad whodunit, stay for the whip-smart, heart-hurt, very entertaining heroine.